As you're probably aware, this season's MLB All-Star Game will take place Tuesday at Citi Field. That makes this a good time to look at a recurring All-Star uniform phenomenon that debuted in 1964, the previous time the Mets hosted the Midsummer Classic: the case of the mismatched batting helmet.

Here's the deal: If you're a student of All-Star Game history, you probably know that the National League won the 1964 game when Johnny Callison of the Phillies hit a walk-off homer in the bottom of the ninth. What you might not know is that Callison had forgotten to bring his Phillies batting helmet to the game, so he hit that winning shot while wearing a Mets helmet.

That was, to Uni Watch's knowledge, the earliest example of a player wearing another team's helmet in an All-Star Game. In the 48 All-Star Games that have followed, at least a dozen players and one coach have forgotten (or maybe just not bothered) to bring their helmets to the game, forcing them to don whatever headwear happened to fit their noggins. Many of these players were pitchers who probably never expected to take a turn at bat. But the list also includes a surprising number of position players.

There's something undeniably appealing about seeing a player wearing the uniform of one team and the helmet of another. It's a fun novelty -- like, "Whoa, there's something you don't see every day!" And in an increasingly corporate sports world where everything feels calculated, measured and focus-grouped to death, a simple helmet mix-up is a welcome reminder that things don't always go according to the script.

Here's a breakdown of all the post-1964 All-Star Game helmet mix-ups Uni Watch is aware of (although there probably have been more):

As you can see, the golden age of All-Star Game helmet mix-ups was the 1970s and '80s. Why? Probably because the American League began using the DH in 1973 but pitchers still had to hit in the All-Star Game (unless they were pinch-hit for, as they often were). Many of those AL pitchers never had a batting helmet to begin with. MLB began allowing the DH for All-Star Games played in American League parks in 1989, then imposed the DH for all All-Star Games beginning in 2010. It's no surprise that these rule changes have coincided with a decline in helmet follies. Indeed, of all the bad things you could say about the DH, maybe the worst is that it's removed the fun of seeing a player in another team's helmet.

Do you know of additional All-Star Game helmet switcheroos that weren't mentioned in this column? If so, please speak up.

Paul Lukas is rooting hard for lots of uni oddities in next week's MLB All-Star Game. If you liked this column, you'll probably like his daily Uni Watch website, plus you can follow him on Twitter and Facebook. Want to learn about his Uni Watch Membership Program, be added to his mailing list so you'll always know when a new column has been posted, or just ask him a question? Contact him here.