I came across this MSDN article (May 2006) by Stephen Tolub on Managed Debugging Assistants (MDAs), a CLR feature I was unaware of. Useful article, especially if you are doing any P/Invoke work. MDAs “…provide information on the CLR”s current runtime state and on events that you as a developer could not otherwise access. Some even modify runtime behaviors to help expose otherwise very hard to find bugs.”
There is a listing of all Stephen Tolub’s MSDN articles here.