I cosplay whenever I can get to a convention, or signing event or similar (which is sadly not very often)
I've got quite a few costumes that I do:
John Crichton from Farscape
Cameron Mitchell from Stargate SG-1
Matt Scott from Stargate Universe
Sam T Anders from Battlestar Galactica and
Chuck Bartowski from Chuck are the main ones I do. I've also done Jack Bauer from 24 once and I'm in the process of having an NCIS agent costume made. Photos of some of them can be found here! [http://s165.photobucket.com/albums/u70/Scaper_photos/Costumes/]
It's all good fun, especially when you're in a group - quite a few of my friends have various Stargate costumes and a few of us have Farscape costumes.