Don't forget MyFaultYourFault - an arbitration/dispute resolution service.
This could actually be wildly successful in the startup community, if not for the tiny little fact that most significant disputes don't occur between peers or equals, but rather between sheep (startups) and wolves (BigCo). And any situation in which the sheep are put into the position of negotiating with wolves does not lead to good outcomes, as a surgeon pointed out (http://www.newyorker.com/reporting/2009/06/01/090601fa_fact_...).
SnackOverload - StackOverflow for people who like snacks
CrackedTwoByFour - StackOverflow for people who need refunds for defective building materials
CrackFoSomeHos - StackOverflow for crack whores
StackCoverFlow - this is still StackOverflow, but with a CoverFlow UI