A Bitcoin Arbitrage Bot
Interfaces with MtGox API to look at different currencies being traded. General strategy is to trade through multiple currencies, and get a return once back in BTC or USD. Also looking at trading between exchanges, MtGox competitors, but they are not quite realtime, so it is more challenging.
Interesting files:
For trading within Mt. Gox, looking at various currencies to find a gain, and making all trades simultaneously.
Find best trades to make given the history of Mt. Gox--trying to take into account slippage and delays in trades being made.