how about pac-man?

Basic games such as Pac-man, Tetris and Snake are often good learning excersises, or for a utility to learn from, you could program a calculator.

You shouldn't need too much help designing the interface, just take a look at how the originals did it, and figure out how to copy what they did - make any changes you think appropriate.

You'll probably want to load your maps from external files too btw, it's good practice at something 'real' games do.

I assume from your post you've decided to work on Pac-man. To start with just get the player moving around in a map on screen, then add in the tokens the player needs to eat. Don't worry overly much about your AI till you have the player working, to draw them you can use pretty much the same functions as for the player. There should be plenty of old topics around about the AI used in the game, you may also want to check out the AI forum when you get to that stage.

you dont necasarily need a complicated pathfinding algo to make your enemies follow you. when i did it, i simply had it so that when an enemy hit a wall, he checks where the player is and moves in that direction. i also added a "check for player here" tile to the map editor, and i put these at all the intersections in the maps. this made the AI pretty damn smart. you can check out the game w / the source if you want here.