ActiveLock is an open-source copy protection, software licensing framework for all development enviroments supporting COM+ architecture. Core DLL available in VB2008 and VB6. Samples in C++, C#, Excel/Access VBA and keygens in PHP, ASP.NET available.
Secure P2P Instant Messenger running on .NET Framework 2.0. Uses server to store user information (user name, password, email address, friends list, log in state, IP address) in encrypted form. Uses custom designed symmetric encryption algorithm.
OW.NET -- 1-Wire API port from Java (and J#) to C#. Use the Dallas 1-Wire and iButton chips with standard C# using a serial adapter (also CF.net) or the TMEX drivers on the Windows platform. No J# distribution installation required.