In my spare time, I wrote a MonthCalendar and DatePicker control for Silverlight. It was just a side project for me to learn Silverlight.
Please note that the code snippet is provided under the Microsoft Permissive Liceanse, and I provide it "as is" without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.
If you actually use it.. I'll be interested to know where and how! 🙂