The people at All Games Considered have being doing what they call an RPG buffet. They eat lunch and play a game. So, how does that make it different than any other RPG session. Well, each time they meet they play a different RPG. They also tend to work on old-school games, and going through the various versions in order (like D&D).

How many people would be interested in a 1x per month getting together to do a one or two shot game? DM can change for each game.

Some Games that I have and/or had eperience with:
Gamma World
1st Ed DnD
Advanced DnD
Aftermath
Morrow Project
Star Frontiers
Star Ace
Boot Hill
Traveller
Space Opera