Abs Workout

Dolphin kick on your back with fins works great! Your basic flip turns are also good. Have fun. -GG

Butterfly (body dolphin) and breaststroke (wave style) work the abs fairly well. They incorporate a crunchie movement with every stroke.

You could also try replacing your office chair (TV chair?) with one of those exercise balls - the little movements you're forced to do to maintain balance are supposed to be good for abs and lats.