The end of summer in the northern hemisphere brought more than just cool temperatures and the promise of baseball playoffs. 10gen released version 2.2 of MongoDB, the leading document-based NoSQL data store. This release offers substantial upgrades in data-center awareness and concurrent operations, as well as two very powerful features in the way of a new aggregation framework and expiring collections. In this article I'll explore the aggregation framework and expiring collections. I'll also briefly discuss some of the concurrency improvements availble in 2.2.