The padded (yet still sturdy) edge of your couch makes the perfect tool for assisted triceps dips. You can cushion your wrists while challenging your arms with a full range of motion.
How to do it: Sit on the edge of the couch with hands just outside of your hips, fingers forward. Lift your body up and walk your feet out until your knees are directly above your heels. Bend your elbows about 90 degrees, lowering your hips towards the floor. Press body up, extending elbows. Try up to 3 sets of 15 reps. Keep your backside close and parallel to the couch during the entire movement -- don't let your hips move away