What does HackerNews think of libgdx?
Desktop/Android/HTML5/iOS Java game development framework
AFAIK the team behind both libgdx and Spine are quite good at giving back to the community. After libgdx they quit their day jobs and went full-time as Esoteric Software [3] and did an excellent job following through with Spine's two kickstarters.
I think this is very relevant to HN not only because of the guys' open source contributions but also their entrepreneurial history (success?).
[1] https://github.com/libgdx/libgdx [2] https://github.com/EsotericSoftware/spine-runtimes [3] http://esotericsoftware.com/
(I'm not affiliated with ES but was a backer of Spine and am a user of libgdx)
Mario Zechner (the main guy behind libGDX) wrote an excellent book[3] last year on Android gamedev that has you start from the basics up to creating your own game engine and games.
[1] http://code.google.com/p/libgdx/
[2] https://github.com/libgdx/libgdx
[3] http://www.amazon.com/gp/product/1430230428/ref=as_li_ss_tl?...