Holiday Gift: Duke Nukem 3D (Win+Mac)

Duke Nukem 3d for PC & Mac is free to download until Friday 14.59pm. PC obviously means Windows executable here but check out eduke32, a modified game engine that will let you play it on Linux. You need to sign up for an account but just use a disposable email as you can download the game straight away without confirming the address. Thanks to Edward Koenig for the tip. Oh yes, and you get some cool artwork and ringtones, too.
[Edit: Well, the Zip file for the Atomic Edition linux version can just be torrented for free anyway.]