I always had the feeling that the computer chooses the pieces just to annoy me rather than randomly. So I programmed a game to prove it. Eviltris is tetris-like game, except that the "random" order of piece selection is a bit different than the standard "random" number generator method.

This game is available as open source, compilable on linux and Mac OS X (and maybe on other systems as well) at:
http://www.sourceforge.net/projects/eviltris