Here’s a high level solo to challenge your entire group in a Gamma Heroes game.
Many players of D&D Gamma World have noted that the game isn’t much different from a superhero roleplaying game; the origins and powers are quite similar to those found in superhero comic books.
These house rules tell how to adapt the D&D Gamma World rules to use in a contemporary setting as a campaign of superheroes.
Update: I just put together a one-page character sheet (use power cards for novice/utility/expert powers) for Gamma Heroes: