I'm mainly running my own system, Brighter Worlds, which is based on Cairn, Electric Bastionland, and Macchiato Monsters (with plenty of other stuff thrown in). My primary campaign is a big hex crawl in which I have scattered all of the various RPG modules I've purchased and want to run, and my players wander around causing problems and knocking down wizard towers (they have a strange vendetta against wizards).

Because I'm still playtesting the system we often pause the campaign for little 1-3 session games to test out new stuff, or to test my other game Meteor my "I want to play Mothership modules but would rather be using ITO/Cairn mechanics" hack.

My other group is much more scattered and we do one shots of various stuff constantly, most recently I ran a CBR+PNK one shot that was a ton of fun.