DbEntry.Net (Leafing Framework) is a lightweight, high performance ORM compnent for .Net. It provides MVC, IoC framework as well.

Open Dataset eXtensions is a quite tiny but extremely powerful ORM framework. It utilizes all the power of ADO.NET and adds the natural ease of OOP. ODX delivers on-the-fly proxy generation, remoting, powerfull offline layer, savepoints/undo, persistent snapshots, SQL/XML datasource, paging, custom SQLs, etc.