What's a good iOS game to help me unwind after a long day of dealing with vendors and contractors?

Look, after a day of negotiating prices and chasing down invoices, my brain's fried. I need something that doesn't require a ton of focus but still keeps me from just vegging out in front of the TV. Piano Star fits the bill perfectly. It's got that tap-the-tiles gameplay, which is easy to pick up, and the music is actually pretty decent. I can play a few songs while I'm waiting for dinner to cook or just before bed. It's a good way to de-stress without getting sucked into some complicated strategy game. Plus, it's free, so the bottom line is it doesn't cost me anything to relax a little. Worth a shot if you need something simple to unwind with.