While at MIT, I took a few classes that had a final projects as a requirement. Some of the projects were more successful than others, but in my opinion, all of them were interesting.
Centipede
As part of the Embodied Intelligence class that I took (taught by Rodney Brooks), we decided to build robots that used the subsumption architecture. The complex behavior we wanted to achieve was "following" behavior. That is, given multiple robots, have them locate each other and form a line. This complex behavior is simply a combination of simple behaviors such as collision avoidance. You can find out more about the Centipede project on this webpage.
COMET
The conventional method for downloading files in the computer network is to establish a single connection between a client and a single server. The total download time in this scenario depends heavily on the network traffic across the single route between the client and server. During a file transfer, the throughput can drop significantly when sudden surges of heavy traffic crosses any point on the path. A connection may have to be restarted when the congestion is too heavy or when any of the routers along the path fails.
In the COMET project, we explore the idea of accessing data in parallel at the wide-area network level to help increase the performance of downstream data transfers. By downloading various fragments of a file in parallel across multiple servers and adapt to the changing conditions of each path, this simple system can take advantage of the aggregate bandwidth of the multiple network paths and avoid pockets of heavy network congestions.