Kind of like the modern equivalent of hiding a comic book inside the textbook you're supposed to be studying, someone has hacked and loaded a Sega Genesis emulator onto the Nook Simple Touch ebook reader. So instead of reading at the back of the classroom, you can spend your time chasing rings.
The hack itself is not very difficult given the Nook natively runs Android 2.1, but since the displays on e-ink devices are notoriously slow to refresh, it also requires the use of an app called NoRefresh to keep the action fluid. But the results look surprisingly playable. There's a slight delay with the controls, but that's a small price to pay when it means you can enjoy a game of Sonic when you should be reading Sartre. [E-Reader-info via SlashGear]