The third Humble Indie Bundle is officially underway (fourth if you count the Frozenbyte-specific event), allowing you to buy a pack of casual games for dramatically less than their usual retail price while simultaneously donating a few bucks to charities. For the unfamiliar, the Humble Indie Bundle lets you purchase five indie games for any amount you deem fair -- be that a buck or a grand -- and you can divide that sum between the developers, the event organizers, the EFF and Child's Play in any denomination you want.
This time around, the bundle includes Cogs, VVVVVV, And Yet It Moves, Crayon Physics Deluxe, and Hammerfight -- a healthy mixture of puzzlers and platformers (barring Hammerfight, which is more action-oriented). The first two are particularly popular among gaming communities as they've been featured in many Steam sales. Speaking of which, it's worth noting that all of the games can be redeemed on Valve's digital distribution platform as well as Desura if you'd like to add them to your existing digital library.
We should also note that all of the titles are compatible with Windows, Mac and Linux, and they're DRM-free so you can play them across all your systems with no hassles. As with previous Humble events, Minecraft creator Notch has secured the top donation spot by sending $2,000. So far, the event has pulled in more than $124,000 and the average purchase amount is $4.19 ($3.43 from Windows users, $5.49 from Mac and $10.37 via Linux). The event ends in just over two weeks, so you have plenty of time to participate.