Squatty Bird is free on App Store

Squatty Bird is a fitness game for iPhone that makes you exercise to play. Prop your phone up somewhere it can see your whole body, then squat to make a puffin flap through a course of obstacles. Deeper squats give you stronger flaps, so you'll need good form if you want to clear the tougher gaps.

It's a lighthearted game. It's meant for anyone who wants a sillier way to get some squats in, and chasing a high score makes it easy to lose count of how many you've done. If you're new to exercise, don't push too hard at first.

It usually costs $2.99 and is free right now, with no end date given. Once you've claimed it, it stays in your App Store purchases and you can download it again after the price goes back up.