So I want to make a little something over the summer before I go off to uni but I really don't want to spend time on doing art so I was wondering if anyone can think of some fun ideas for games that involve only basic primitive shapes and colours (e.g. Cubes, triangles, spheres etc.). All I've come up with is some sort of simple tower building strategy game.

Any card game, like solitaire variants, letter games like scrabble and boggle (letters count as basic shapes since you can just type them instead of drawing them right?), and many speedpuzzle game like tetris, puyo puyo, and bejeweled.

Or you could do a Rogue-like; using ASCII tiles in place of graphics.

You can find free artwork to be used in non commercial (and even places where you can sued them commercial) on the net, so doing art for little projects is not that great a problem. A google search should locate various sites that offer such services.