
Penny - “Do you think my nephew would like this (comic book)?”
Sheldon - “Perfect. He just has to be familiar with Infinite Crisis, 52, Countdown, Final Crisis and the re-emergence of the multiverse.”
Penny - “What’s the Multiverse?”
Sheldon - ….exactly.
First of all, with no small shame, I admit that I caught and understood every single Batman comic book reference on last night's show. And yes, any idiot who thinks that back-from-the-dead Jason Todd* should become Batman following the (temporary/stupid) death of Bruce Wayne deserves to not score with Penny.

No real point to this post. The Big Bang Theory has quickly become my wife's favorite show and my second favorite sitcom behind Scrubs, and I just felt like writing about it.
Scott Mendelson

Anyway, the original idea was for Dick Grayson (Robin #1) to perish in the major DC event of that year, Infinite Crisis. Thus a reanimated Jason Todd would take his place as Nightwing, Grayson's current superhero alias. Alas, the character of Superboy became tangled in a lawsuit involving DC Comics and the heirs of Superman creators Jerry Siegel and Joe Shuster over character rights and residuals. Thus, in a completely unrelated coincidence, Dick Grayson was spared and Superboy instead perished in the sixth issue of Infinite Crisis. So now the DC universe was left with two former Robins, one who was supposed to be long dead and another who was supposed to be newly deceased. Strained retconning and terrible storytelling ensued.
I'm sorry for the digression, I just love telling that story for the same reason I love telling the story of New Coke.