If you'd wanted to play 1992 platforming trilogy Jill of the Jungle last week, you would've probably had to do it illegally—but now it's available on GOG, and it's completely free.
The trilogy, which was designed by now Epic Games CEO Tim Sweeney (when the company was still called Epic MegaGames), consists of Jill of the Jungle, Jill Goes Underground and Jill Saves the Prince, and they're all included in the package. GOG hasn't set an end date for the freebie deal, so presumably it'll stay free forever. You can grab it here.
The cult classic sees you control Jill as she swings, jumps and kicks her way through the jungle-themed levels. If you find magical icons, then Jill will transform into various animals, including a flaming bird or a fish that shoots bullets.
Flick through the screenshots on the GOG page to find out what to expect. I presume it won't be massively popular with people that didn't play the original, but for nostalgia hunters, it's a goldmine—and a completely free one at that.