I was just running through the steps for setting up an AD RMS development environment and I was on the Activate the Development Environment step. One of the options is to run the MachineActivation sample included with the Windows SDK to activate the client computer.
I opened the solution in Visual Studio 2005 and tried to build it, but it skipped the project. I had to set the Configuration to Release and the Platform to Win32 (Configuration Properties) in order to build the project. However, there was a build error. The project was attempting to create a Release directory and didn't have permission. To get past this, I turned off User Access Control (let me know if there is a better way to deal with this) and the project built successfully.
After performing these steps I was able to run MachineActivation.exe and activate the machine.