I present to you R7 along with the grandest scenario yet: Cataclysm. (Yes, it's named after the cool zombie apocalypse survival roguelike which you can find here.)
A virus of alien origin suddenly descends on a town where a small group of X-COM operatives happen to be enjoying some R&R. It's time to show those aliens what off-duty X-COM soldiers can really do! WE'RE GONNA... wait a minute... we're off duty... we don't have any weapons... or armor... or anything except our wits and a sledgehammer in the garage. ****.
Sounds downright... infectious!