CLR Proc Container
The CLR Proc Container is free software that enhances the capabilities of SQL Server stored procedures by opening a door to the .NET world. Code written in any .NET language can be invoked from stored procedures, providing stored procedures all the functionality of the full .NET runtime. Named procedures can be defined in .NET, dynamic procedures can be created and run, and binary objects passed between stored procedure code and the .NET object.

DBMethods
DBMethods is a library that allows you to express parameterized SQL and stored procedures as managed code functions in your language of choice (Visual C#, Visual Basic .NET, Visual J# .NET and others) using Microsoft's .NET Framework.