"Raspberry Pi"s are credit card-sized (or smaller) computers. Modern versions are powerful enough to emulate a bunch of gaming consoles. They're tiny, cheap, and energy efficient. They're also a great way to get started with other fun projects: home automation, media centers, robot cars, and more.
Don't say I didn't warn you
The majority of my issues are actually with the OS. I have "some" experience with Linux, but I still bump into issues from time to time. Most end up being solvable, but might involve (at its worst) re-imaging your SD card ... after wasting N hours/days trying a bunch of commands you don't fully understsand. At best, you need to learn a little bit more about Linux each time you solve an issue.