I have a workout routine I do on my balance ball.
30 mins warmup on the fixie and rollers
3 x 10
one-legged squats (per leg)
3 x 10
one-legged ball lunge (per leg)
3 x 10 calf raises
3 x 10 push ups
3 x 10 tricep dips
3 x 25 ball crunches
3 x 10
back extensions
3 x 10
seated ball twist with the balance ball instead of a medicine ball
3 x 10
hip extensions
3 x 10
ball twists (pushup)
I do mine in circuits, but you can do them however you want.
Then I cool down for 30 mins on the fixie and rollers. Finish with stretching.