Löve is an awesome framework you can use to make 2D games in Lua. It's free, open-source, and works on Windows, Mac OS X and Linux.
Every Stabyourself.net game was made with Löve (and love).
function love.draw() love.graphics.print('Hello World!', 400, 300) end
Some things made with LöveEdit
(That aren't from Sys)