I'd like to see one of the Seinfeld experts write a quiz just on the Seinfeld Superman/Superhero connection. There is a reference in the majority of episodes.

I have been planning a series of Seinfeld quizzes on various topics, but I didn't want to finish them until I'd covered the whole series. To do this, I'd need the final three seasons on DVD.
I need to be a perfectionist like that.

I read somewhere that there is a superman reference in every Seinfeld episode... even if its only a glimpse at a statue on his shelves.
In fact, I beleive it was a drinking game at my college and roomates of mine proved it.

This isn't a full list, but it gets you started....
http://www.seinology.com/lists/list-superman.shtml