Yup, the SNAPSHOT isolation level, which was added in SQL 2005.

There are two flavors - "regular" static snapshot, and a "dynamic" snapshot which effectively turns every READ COMMITTED query into a dynamic snapshot.

Unlike other isolation levels that work with shared and write locks, SNAPSHOT works by versioning in TempDB.

It's not for every situation, but in certain circumstances is a great help.

My weekly blog post this Saturday will cover some scenarios.