NoSQL Datastore component
Write a portable data store component over a number of 'NoSQL' databases (Apache Cassandra, Couchdb, Hadoop/Hbase and AppEngine Datastore databases.)
This could be one component (written in Python or Java) or a set of components (one per database) all implementing the same REST data store interface, allowing applications to store data in different NoSQL databases without having to worry about the details and API differences between the databases.
The project could start with just one or two databases and add more databases as we go. This should be a really good opportunity for students to experiment with these new NoSQL databases.