I have also been part of the following startups.
Delivery From Mars. An on campus food deliver application that uses a peer-to-peer network to connect individuals wanting food and grabbing food. Includes a rewards program to incentivize users to recurrently use the application.
Fix My Tech Now. Provide software and hardware repairs for laptops, desktops, Xbox, Xbox 360 and PS3.
Bitcoin Arbitrage. Buy and sell bitcoins at a high profit margin. For efficiency and to reduce mundane tasks inherent in such a system, we created a software (available on GitHub) to stream line this process.