Cooper Allen

USA TODAY

It's become cliché to say of an upcoming campaign event that the "stakes are high," but for Donald Trump on Sunday night, that has never been more true.

The Republican presidential nominee was already facing a defining moment in his campaign following a poorly received opening debate performance on Long Island late last month. Now, as his candidacy seems to be teetering on the brink following the release of a 2005 recording that depicted the real estate mogul using graphic language as he describes groping women, Trump needs nothing short of a Hail Mary to revive his hopes of overtaking Hillary Clinton.

Here's what you need to know as the two square off at Washington University in St. Louis for their second of three scheduled debates.

When does it start?

As with all the debates, Trump-Clinton II begins at 9 p.m. ET and will last 90 minutes.

Where can I watch it?

It'll be hard to miss. All of the broadcast networks (except NBC, which will be airing the Giants vs. Packers Sunday Night Football game) will televise the debate, as will all the cable news channels. You can also live stream it on any number of websites, including USATODAY.com.

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Who's moderating?

CNN's Anderson Cooper and ABC News' Martha Raddatz will be at the helm in St. Louis on Sunday night. Steve Scully of C-SPAN is the designated back-up moderator, a role he's playing at all the debates should someone fall ill.

Anything different about this debate?

There is. The format will be a town meeting, which means half the questions will be posed by the moderators, while the rest will be asked by undecided voters chosen by Gallup, according to the Commission on Presidential Debates. The questions from the moderators, the commission says, will cover "topics of broad public interest as reflected in social media and other sources." So, basically, they could be about anything. Trump and Clinton will have two minutes to respond, and Raddatz and Cooper will get another minute to "facilitate further discussion."

Is it Trump or Clinton?

2016 Poll Tracker - USA TODAY

After this, what's next on the debate schedule?

Brace yourself, but after Sunday night you'll only get one more chance to see Trump and Clinton on the debate stage. That'll come Oct. 19 in Las Vegas, and Chris Wallace of Fox News will moderate.

Any notable town hall debate moments from years past?

The different dynamic from other debate formats, with candidates walking around a stage while taking questions from voters rather just a single moderator, has at times tripped up candidates.

Take this famous moment from a 1992 debate, where President George H.W. Bush looked at his watch right before a voter asked him how the national debt had affected him personally:

Contrast that with then-Arkansas governor Bill Clinton's answer to the same question, in which he makes a point to ask the voter how it's affected her before describing how Washington policies had ravaged his small state. "In my state, when people lose their jobs, there's a good chance I'll know 'em by their names," Clinton said. "When a factory closes, I know the people who ran it. When the businesses go bankrupt, I know them."

Then there was the 2000 town-hall debate between then-Texas governor George W. Bush and Al Gore, the incumbent vice president. Gore, seeking to put Bush on the spot about whether he supported the "Dingell-Norwood bill," the most prominent patients bill of rights legislation then being considered on Capitol Hill, approached the Texas governor and got a bit closer than expected. Bush glanced at Gore and gave him a brief nod before finishing his answer, as the crowd chuckled.

It was a good moment for Bush and a classic illustration that debate points aren't always won by trying to outsmart your opponent on policy details, particularly in a format like a town meeting.

• QUIZ: Test your memory of general election debates

Any other sporting events I can distract myself with if I don't want to tune in?

Perish the thought! But yes, if you're over campaign 2016 and aren't much of an NFL fan, Game 3 of the American League Division Series between the Toronto Blue Jays and Texas Rangers will air on TBS at 7:30 p.m. ET.