XCOM UFO Defence is free on the Humble Store right now

You might know it better as UFO: Enemy Unknown.

Rarely does a week go by when some publisher or retailer isn't giving away a game for free. Spending nothing in exchange for something is great, and this is an especially nice offer: the Humble Store is giving away X-COM: UFO Defense, or for those outside of North America, UFO: Enemy Unknown.

It's the first instalment in the XCOM series, of course, and be forewarned that as far as I can remember it was the first game to make me incredibly angry. The offer is valid for another day and a half, so you'd best go and grab it now before you forget.