So I have been sitting on the fence about The Humble Bundle Mojam 2
since they never say what games will get Linux or even Mac support until they put the builds up, but at least the Mojang games do and one is open source too!
You can still buy it until March the 2nd.
Nuclear Pizza War by Team Mojang has a Linux build and is open source as well, I doubt it will be long before it gets on github and picks up new contributors. No news on it's license yet so I won't be linking to the sources until it's license gets explained, hopefully another "do what you want" license like they did with their game on the first bundle.
As usual with this type of quick game making thing the games are all odd with very little to them, I'm all for charity but it does seems a little pointless unless the games are made open sourced or the developers continue on with them after.
It seems most of the Mojang games have a Linux build available and one of the others as it's Flash should work too.