I just ran across this 2010 article detailing some of the Sysinternals tools available from Microsoft. Sysinternals started as a private company run by two smart guys, but their tools were good enough that Microsoft bought the company. The tools are free (of charge) but not open source.
Some of these tools (like Process Explorer) are very popular and used by developers on my team. Others are less known but look like they would be very useful, especially the PS utilities, some of which allow you to identify and kill hung processes. Give them a try.