Planks!
I like doing "planks", because I like the ab control. (and I can only do girl push-ups, too.) Someday when my arms are strong enough for boy push-ups, my abs will be ready!
Prone planks are done in boy-push-up position, but instead of your weight being on your hands, it's on your elbows/forearms. You just hold yourself there for as long as you can without sagging. Then do it again twice more.
Side planks are awesome for giving me a WAIST cuz they really kick in my obliques. You lie on your side, with your weight on the outside of one foot and one forearm. Do 3 times on one side, 3 times on the other.
Yes, I admire my own belly in the bathroom mirror.... It's nice to actually like my stomach again!
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson