So I happened upon this website for creative types that offers fun things to buy, but even better free things. I love free things. If you go here, and scroll to the bottom of the page you can download their activity books that have all sorts of fun things in them. You can download them and print them at home or you can just play with them online. I bet they'd be fun on an ipad... also if you register with them you'll get 10 free credits to buy things with, like these super cool notebooks or this studio sign.
Photo from Veer