My first thought is the Teenage Mutant Ninja Turtles theme. New fortress/megaproject idea: Let's see if someone can replicate the sewers the Turtles live in in the series (the 80s version has some interesting ideas to toss in) under a random city, and have 4 specialized dwarves (sword, quarterstaff, sai, nun-chucks masters with a captain which is a master fighter (optionally all weapons as well); ALT- DF quivalent weapons).
More pop culture megaproject ideas, Dwarf Fortress Ghostbusters. Build/convert a fire station (when added eventually) into HQ, and have your military kill the dead... again.
Another idea is to reproduce Diablo and build a cathedral with layered catacombs that lead into the hellish depths of the world (remember to unleash Hell as well). Bonus points for building a temple/shrine in Hell as well. Be sure to breed tons of cattle as well to make a cow level, and raise a dwarf child without a leg to sell for ridiculous prices. After all this is done, Adv. Mode it.
One last project idea, or adventure mode craziness. LCS megaproject. Fortress mode, you play conservative (go as far right as possible), Adventure mode, you play Liberal, go as far left as possible.