http://www.garry.tv/?p=270
Someone asked a while ago if Garry's Mod would be able to have characters inflate. The answer back then was no, because we thought that there had to be inflation animations for said model.
Well, not anymore. Garry is working on a tool that will cause the body parts of character models to grow and inflate.
So, think Poser, but easier to manage (and cheaper to own, if you already own Half-Life 2).
wow awesome... bring on a blimp rifle mod a la Unreal Tournament and some good female characters to blow up!