you don' continue with navy tradition and do scissor kicks?
for abs, i do 10 minutes each workout day. and it varies.
standard crunches
leg lifts, and i really concentrate on my form
side to side crunches (meaning i'll come up off the floor and go side-to-side touching the heels of my feet)
obligue crunches (upper body lying flat on the deck, then both knees turned either right/left)
V crunches (legs up in the air straight and as i lift my upper body, i lift my pelvis off the deck)
leg lowers (feet straight up and
slowly drop them down until i feel my lower back starting to come off the deck)
reverse crunches
edit: oh, and my set/reps goal is 3 sets of 15-20 reps (for the upper abs, i can get the 20, but for the lower abs, i can get to about 15 before my form fails me)