Inexpensive game pad for OS X? I'm setting up a Mac mini for my entertainment center, and would occasionally like to be able to play games withough having to set up the keyboard and mouse.

Are there cheap Bluetooth game pads that would be suitable for moderate action games, such as Portal 2?

I don't need fast twitch gaming, and if it could double as the remote for plex or mythtv that would be better.

Cost is a big issue, though.  I've had to fish out more than a few things from the fish tank due to the kids.
Macally makes two USB-based game controllers that are OS X compatible. Both are around USD$30 at the time of writing on Amazon.

Macally ISHOCKX



Macally ISHOCKII



Sony DualShock 3



You can also pair a Sony Playstation DualShock 3 bluetooth wireless controller with OS X without the need for any additional drivers. Everything you need is built right in to Snow Leopard and Lion.

Press the PlayStation logo on the controller and OS X should show the controller in the list of available devices to pair with under the BlueTooth menu bar list. Once paired you'll need to map the buttons to key actions so it works with your games. For that  you can use the GamePad Companion app from the App Store.