HaloMD

Play Halo 1 multiplayer online for free (on your Mac)

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And if you have an Xbox 360 controller, you can play like the good old days with these OSX drivers: https://github.com/360Controller...
It's Halo. For MAC!
This is why I love the Internet. Also, just got pwnd hard without a mouse.
*calls in sick*
*orders Xbox 360 controller*