I'm using MongoDB 1.8.2 and mongo-csharp-driver 126.96.36.19984 (IIS 7.5/.Net 4.0 x64).
The Web Server memory is increasing after every select (about 10,000 results in the cursor) -> which leads very fast to > 2 GB memory usage.
The memory is never released anymore and only an application pool recycle can free the memory.
It seems that Console Applications and Web Applications hosted in VS built in Dev Web Server don't have the Problem.
Sample Web Application is attached to reproduce the problem.