LÖVE

Materials, lectures and slides about game design : github-dpengineclub

A great tutorial series about implementing Tile-Based games: see Tonypa's blog.
They are meant for Flash programmers, but most explanations are language-agnostic. Enjoy!

A nice series of articles about pathfinding.
Found @Ai-depot.

Online procedural music generator: http://www.abundant-music.com/

Game Art Tutorials for programmers @2dgameartforprogrammers.
A nice post on character animation can be found there.

Vadi wrote:Free sound generator, works on Linux and windows: http://delirare.com/ports/sfxr-sdl.tar.gz

And Mac! Don't forget cfxr.

http://open.commonly.cc/

The open art bundle!

Do you need help when it comes to choosing a license ?
@Markgo: Awesome, thanks!

here is a great tool for making explosion sprites.

http://www.positech.co.uk/content/explo ... rator.html

A great blog for programmers about game art: http://2dgameartforprogrammers.blogspot.de/