Earth Delta is Lizard’s take on post-apocalyptic mutant roleplaying (a la Gamma World), done with the Dungeons & Dragons 4e ruleset. Yes, I know Wizards of the Coast has one. Earth Delta differs from Gamma World 4e in the following ways:
It’s not finished yet, but when it is, it will cover levels 1-30 and be completely compatible with 4e.
It allows for all the gonzo you could want (dude, the mascot is a flying grizzly bear with laser eyes!), but it doesn’t assume the game has to be a wacky beer-and-pretzels time filler for when someone can’t make it for your D&D game. You can run the game straight or silly or anywhere in between. I give you the tools; you decide what to build.