Grunty Guy (very aptly named, they even put up posters saying no grunting!! -actually I don't agree with that rule, but this guy is really funny to hear)
Hang Man - he just likes to stretch it out on the chin up bar
The pair of Jokers - these guys don't know how to lift properly & it's just funny watching them swing the bar all over the place :)
Smarmy Guy - he just has this spooky serene smile plastered on his face ALL the time
The running man - I don't think I've done cardio without him running (& sweating profusely) on the Tredmill
The Beefcake buddies - these are so big, burly & tough that they can just leave the heavy DB's around the place after their workout for other people to clean up (grrrrr, I used to have to put them away when I worked at the gym)
And of course the towel sitters - this is where your towel acts as a babysitter for the piece of equipment you have reserved for yourself. C'mon people, what happened to 'working in'??
Anyway, these are just a few - I'd love to hear about your characters, all in good fun of course!