~~~Name 3 superheroes in under 5 seconds.~~~
As I recall it, there were two or three people ahead of me, and none but one of them had any idea of anything superhero related. So the guy closest to me, the only one with any superhero knowledge, was about to take his shot at naming 3 in 5. I don't remember the 3 he named exactly, but it was something like, "Superman. Batman. Robin."

Where the "nerd epic fail moment" occurred was directly following my victory in the Sidekick ~OR~ Superhero debate. It was my turn, and I had only 5 seconds to name 3 superheroes that had not been previously named during the course of the game. I had rehearsed my answer over and over and over again in my head during the debate aforementioned.
Sadly, I totally froze and could only name two. Needless to say, I hung my head very low in nerd-shame for the rest of the evening. Very, very low.