Running With Scissors' controversial shooting game, Postal, originally came out in 1997. Now, after almost 2 decades, it has become open-source. This means one can now legally tweak the game as he/she wants; that includes porting it to other platforms. The source code is now available on Bitbucket. The devs are calling it a "belated Christmas present".
The official announcement on Running With Scissors' website reads, "It’s definitely been a wild ride for us all, and POSTAL means a lot to us – it’s our baby… But now we’re ready to hand the future of ‘the little shooter that could’ to the public at large. People have been asking, and we have been promising this for years now, but today we are proud to announce that the source code for POSTAL is officially released to the public on Bitbucket, under the GPL2 license. Everyone now has ‘under the hood’ access, to see what makes POSTAL tick, and anyone with the time and skills can now tweak/change/update/modify anything in the game at all! And hey, if anyone feels the urge to port the game to other platforms (The Dreamcast, for example *wink* *wink*), then they absolutely can!"
If you want to read the whole announcement, click this.