Not much explanation necessary here. It's a periodic table, only with video game characters instead of those boring chemical elements.
While some are a bit of a cop-out (Batman and Iron Man aren't game characters, per se), the rest is a great mix, crossing decades, platforms and even sensibilities. Bonus points are awarded for not just visiting Day of the Tentacle's well, but returning to it.
IHC's Periodic Table of Video Game Characters [I Heart Chaos]