A NoRM-MongoDB Repository Base Class
Always persisting object graphs using the embedded document strategy may not be such a good idea even if it sounds like a good strategy which even works well with MongoDB advanced filtering capabilities:
NoRM makes persisting POCOs to a MongoDB collection simple. Object graphs are automatically serialized to a BSON document.
Think about your data firstly.
via: http://www.codevoyeur.com/Articles/20/A-NoRM-MongoDB-Repository-Base-Class.aspx