Tetris, Arkanoid, Asteroids... these all have been done gzillion times before but they should teach you how to load, move etc stuff using Blitz3D. No need to plan the next "DOOM3 killer" for your first project.
Be sure to check out these tutorials:
http://www.blitzcoder.com/articles.shtml
Be sure to check out these tutorials:
http://www.blitzcoder.com/articles.shtml