What are some effective ab exercises that don't require me to get on the floor?

This one you don't have to get on the floor, just the couch or a bench!
Lie on a couch or bench, that allows your back to hang off freely, place your calves, on the top the couch (or wall), at a 90 degree angle, Place your hands behind your head, raise your head and shoulders toward your knees, keep back rounded, with a 2-4 inch travel, Raise pelivs and round your back as you curl your torso up toward your knees, Hold 2-3 seconds, 15-25 reps.

Sit upright on a chair, cross arms on chest, lightly contract your abs muscles, Hold 5 seconds. Rotate to your left as far as possible, kepping hips, square forward, Once you have reached your end range, hold position 5 seconds, Return to starting position, repeat on right side, 2 sets, 15-20 reps, work up to 3 sets, 20-25 reps

Standing upright, lightly contract your abs and hold 5-10 seconds, Bending at waist, sliode your left hand as fat down the side of your left leg as possible, without tilting forward or backward---hold--- Slowly pull your body back up, Repeat on right side 2 sets, 15-20 reps, work up to 3 sets, 20-25 reps.

Try these, if you need more--have about 5 more great ones!

I'll hear five others while you are at it, please.