Six developers feature in Mojam 2013. (All rights reserved - Mojang)

Minecraft developer Mojang has four days in which to create a game during its second annual Mojam, as one of six studios taking part in a pay-what-you-want charity drive, with activity broadcast live online.

Sold via the Humble Bundle website, vendor of over twenty charity-focused assortments since May 2010, each studio has until midnight on February 23 to come up with something for the Bundle's backers to download and play.

Also involved are Wolfire Games, which founded the Humble Bundle website, alongside fellow independent outfits Ludosity ("Boulder Dash 3D XL," "Garden Gnome Carnage"), Vlambeer ("Super Crate Box," "Serious Sam: The Random Encounter"), Mojang collaborator Oxeye ("Cobalt"), and Grapefrukt (the upcoming "Rymdkapsel").

As usual, visitors to the Humble Bundle website can decide how their contributions are distributed, with the Electronic Frontier Foundation and Block by Block the benefactors; the participating developers and Humble admins have elected to forgo their cut.

Last year's Mojam resulted in "Catacomb Snatch," with Oxeye's "Fists of Resistance" and Wolfire's "The Broadside Express" also sent to the bundle's supporters.

Other game bundles currently offered by other vendors include the Greenlight Bundle #3, Free Bundle #3, Groupees' Be Mine Anniversary, and Bundle Stars 1, 2 and 3.

Official website: humblebundle.com