Michael Calkins (Login MCalkins) Moderator Posted Jul 3, 2012 9:39 AM
a card game (skip-bo, hearts, spades, or free cell). In case of freecell, maybe you could make a solver. In the case of one of the other three, maybe you could make a computer AI player, or even human vs human multiplayer capability across a network.
a monopoly game, allowing normal variations in the rules. Again, you could do computer AI players or network multiplayer capability.
perhaps an interpreter / script host / virtual machine of some kind. Perhaps invent your own language. Perhaps simulate a multitasking CPU.
perhaps a good hex editor, capable of editing multiple large files. You could give it search, as well as cut/copy/paste in the same file and between files.
perhaps, investigate, understand, and implement various algorithms, such as cryptographic hashes like SHA-1 and SHA-2. Perhaps symmetric key ciphers like AES. Perhaps asymmetric key ciphers, like RSA, or ciphers basic on elliptic curves. Perhaps pseudo-random number generators. Perhaps compression algorithms.