If you want an alternative to the good suggestions that others have already provided, you might like the recent game "Human Resource Machine"[1], by the creator

If you want an alternative to the good suggestions that others have already provided, you might like the recent game "Human Resource Machine"[1], by the creators of "World Of Goo". As they describe the game: Your office is a simple computer. ... You might describe this machine as Harvard Architecture with a single accumulator. Don't think of it so much as a game, but a fun interactive CPU that you program in assembler. It starts with how to use basic opcodes (I/O, math) and registers ("save a copy on the floor"). Conditional jumps (w/ an implicit flag register) are gradually added, and later puzzles use indirect addressing a lot. [1] http://tomorrowcorporation.com/humanresourcemachine http://tomorrowcorporation.com/humanresourcemachine