Plus: Playing at Wembley over and over and over again; the shortest time between two penalties (2); and when players attack – with corner flags. Send your questions and answers to knowledge@guardian.co.uk and follow us on Twitter

"Which is the least successful testimonial match ever?" tweets Matthew Britton. "Has one ever been done at a loss to the player and club?"

Success, where testimonials are concerned, is somewhat subjective. It's fair to suggest the 17-man brawl that enlivened Julian Dicks' testimonial was a bonus for fans who attended, though hardly conducive to an afternoon of backslappery. And take Johan Cruyff's farewell fixture for Ajax against Bayern Munich. You might think the result doesn't matter in a testimonial and, by and large, you'd be right, but what about when the team you invite turn up and give you a proper shoeing?

"The German champions wanted to show their Dutch counterparts something after earlier defeats and not being welcomed at Schiphol Airport," writes Dave G Boham. "They even had to sleep at a sub-par hotel. After jeers from the crowd, they showed their hosts something. Three goals were disallowed during the 8-0 hammering dished out by the Bavarians. The Ajax players just wanted to have a good time. In 2006, Bayern apologised."

Perhaps the most painful of the testimonial failures is the "disappointingly low turnout". "In April 2008, Darren Wrack's testimonial at Walsall pulled in a crowd of just 1,330 (207 away supporters)," writes Rob Davies of the man who played more than 300 games for the Saddlers. "This was probably due to the huge downpour and the possibility that any money Wrack made would have gone to paying off his gambling debts." A couple of months later Wrack sought help for his problems and he now works as a scout.

And finally there's the testimonial that you have fork out £100,000 just to play. Anders Rokstad points out that Southampton's Scandinavian stalwart Claus Lundekvam had to do just that for his testimonial in 2008 after Bon Jovi made a mess of the St Mary's pitch. With Celtic, Lundekvam's desired opponents, only able to make a handful of dates, there was no time for the Saints to reseed the pitch after the popular American beat-combo had finished belting out Livin' on a Prayer and Keep the Faith. Lundekvam, though, stumped up for an emergency job.

"Claus has sacrificed a lot of money to put the game on with Celtic and the thing with Claus is that he wants an opportunity to say goodbye to everybody," said Matt Le Tissier. "He's the kind of guy if the game just breaks even and everybody has a great night he'll be delighted.

"Claus had his heart set on getting Celtic down because of Gordon Strachan who was his favourite manager. Celtic have done us a bit of a favour as well by reducing the fee they usually charge for a testimonial so we thank Celtic for that but it's costing quite a lot of money to put the game on.

"As a testimonial committee we've had to purchase a pitch and that doesn't come cheap. It was the only way we could get Celtic and we've taken that risk in the hope that the fans turn out in their numbers and make it a great night for us."

In the end 18,664 fans turned up, meaning Lundekvam just about recouped his money.

MOST SUCCESSIVE WEMBLEY APPEARANCES

"With Rio Ferdinand having played his last two games at Wembley for Manchester United against Barcelona and then for England on Saturday against Switzerland, his next competitive game will likely be against Manchester City at Wembley again," notes Conan Jal. "What is the most consecutive Wembley appearances a player has made without playing at another ground in between?"

Jonnie Dance suggests Glenn Hoddle, who played five in a row at Wembley in 1981: the FA Cup final, the FA Cup final replay, two British Championship matches and then the Charity Shield.

There were plenty of readers suggesting Gary Neville, who played in the 1996 FA Cup final, for England at Euro 96 and the Charity Shield later in the summer. But the Manchester United stalwart was suspended for the semi-final against Germany, meaning that he played six successive competitive matches at Wembley (if we count the Charity Shield as competitive). Alan Shearer played in all five Euro 96 games and then the very same Charity Shield, giving the pea-loving striker-turned pundit a Neville-equalling six in a row.

Seven of England's victorious 1966 World Cup side – Gordon Banks, George Cohen, Nobby Stiles, Jack Charlton, Bobby Moore, Bobby Charlton and Roger Hunt – played six in a row at Wembley in 1966, but they are all eclipsed by Ray Wilson, who played in Everton's 1966 FA Cup final triumph before the tournament, giving him seven straight competitive games (England had, of course, played several friendlies overseas prior to the World Cup) at Wembley. It would have been eight had the Charity Shield not been played at Goodison before the 1966-67 season.

Potentially, though, even Wilson could be eclipsed. AFC Ealing played eight home league games at the stadium in 1930-31, and, though unlikely, it's not inconceivable that a member of the Ealing squad could have made eight successive appearances at the ground.

THE SHORTEST TIME BETWEEN TWO PENALTIES (2)

Last week we looked at teams conceding two penalties in (very) quick succession. But those incidents concentrated on hapless defending, so to even things up we head to Germany and some equally useless spot-kick-taking.

"I remembered this German Zweite Bundesliga match I visited – Aachen v Bochum," writes Bochum native Malte Strohmann. "There were about 20 seconds between the save and the second blow of the whistle, but the second penalty was also missed, it hit the bar. What a luck for my team, who won the match 3-1. The last goal was even a penalty for Bochum." So is this the shortest time between two missed penalties? Quite possibly.

And, though not strictly speaking an answer, we were intrigued by this tale from the 1999 MLS – a penalty awarded in the middle of a shootout. "In 1999, in a Major League Soccer game at Giants Stadium involving the NY/NJ MetroStars and a team I can't recall," begins Brian Scorben, "the game finished level and went to the shootout that the league has since done away with (the one used in the NASL days where a player breaks in on the goalkeeper from 30 yards away). During one effort, the goalkeeper dove at the feet of the attacking player, fouling him and prompting the referee to award a standard penalty kick."

We've searched high and low for footage or more details and the best we've managed is to narrow it down to one of four fixtures – the visit of LA Galaxy in April, the visit of Tampa Bay in June or either of the visits of the New England Revolution in May and August. Anyone with more information please do get in touch at the usual address.

KNOWLEDGE ARCHIVE

"Have any players ever used a corner flag, a goalpost or an advertising hoarding to attack an opponent?" enquired Pedro Salinas in 2007.

Step forward Canada's Paul Peschisolido, who flipped a corner flag into an El Salvador player's face during a World Cup qualifier in 1997, and duly picked up a red card for his troubles. "I was kicked a few times and the referee wasn't giving anything, while every challenge we made seemed to result in a foul," explained Pesch afterwards. "I was getting very annoyed and frustrated so I decided to elbow one of their players. It was right in the corner and in fact I elbowed the corner flag into his face."

Martin Keown managed the next best thing in January 2002, chucking a corner flag into the stands during Arsenal's 1-1 draw at Elland Road. Early in the game Keown conceded a corner; as he got up he grabbed the flag and casually lobbed it behind him into the front rows of fans. Despite uproar from the supporters, the FA eventually decided he had not intended to hit them, and did not enforce any punishment.

Sadly there were no such exciting tales regarding advertising hoardings, though Rudy Hulsman was quick to remind us of January's match between Orlando Pirates and Black Leopards in South Africa's Premier Soccer League. With the game in mid-flow heavy winds suddenly sent a number of hoardings flying across the pitch, taking out a linesman and several players in a matter of seconds.

For thousands more questions and answers take a trip through the Knowledge archive.

CAN YOU HELP?

"In researching the Everton 1965-66 season, I noticed that they played Sheffield Wednesday in the league in games two and four so had fulfilled their home and away fixtures with each other before the end of August," notes Conan Jal. "Was this a common occurrence or a freak fixture rarity?"

"Seeing the ball in this clip rebound off the crossbar before crossing the line what seems about 10 seconds later, got me thinking," writes Ed Birth. "What is the longest time between a ball being struck and it crossing the goalline?"

"The commentators on the US Spanish language channel Univision, repeatedly use nicknames for soccer players and teams that are not used in other languages," notes Tim Dockery. "For instance, Wayne Rooney is referred to as El Astro Boy, David Beckham is El Spice Boy, Tim Howard is El Pato Howard (Howard the Duck) and the US Men's National Team is El Equipo de Todos (Everybody's Team). What other instances are there of players or teams who have nicknames in a language that in no way correspond to their nicknames in their native tongue?"

"My mates and I were discussing Chris Eubank's sartorial quirks and I wondered if there were any footballers who wore a monocle, either when playing or off the field?" writes Will Shiel Dods

"Following on from your old football-inspired albums question, Iron Maiden's Somewhere in Time has reference to West Ham beating Arsenal 7-3 on the album cover," begins Paul Baker. "Barring the SFA using the iconic Robin Friday at Cardiff image, the Wedding Present's George Best at Man Utd one and Mogwai's Zidane soundtrack (Real Madrid), have any other football teams been referenced on CD album covers?"

"Have any team's B team ever won promotion to the same division as the real team (but not taken it)," asks Adam O'Plum Jr. "Same for relegations."

"What is the longest losing streak in football?" wonders Noel Walsh.

Send your questions and answers to knowledge@guardian.co.uk