No, it isn't the Hydrometerological Prediction Center at NOAA (though they could certainly use it).  It is High Performance Computing.  You computer probably has 2 processors in it (not including the graphics processor) -- wouldn't you like to have thousands, or hundreds of thousands?  HPC is about trying to link together lots of computers, so they can work together computationally.

 We are working on a new product at Microsoft, version 3 of the HPC cluster, and I am the beta engineer on the developer support side of things.  Being able to use all of those processors to solve a problem often requires the code that is solving the problem to be rewritten, breaking down the different parts so they can be processed by different machines.   Some problems are "embarrassingly parallel" (http://en.wikipedia.org/wiki/Embarrassingly_parallel) and this is fairly easy.  Others require far more thought.

One of the great strengths of doing High Performance Computing on Windows is PowerShell -- our scripting language which treats the object, not just a string of text, as primitive. HPC is 100% committed to being able to be configured through PowerShell (see http://technet.microsoft.com/en-us/library/cc947676(WS.10).aspx for the current cmdlets). 

One method I'm constantly using with HPC customers is showing them how to integrate C# and PowerShell (http://blogs.msdn.com/powershell/archive/2006/04/25/583250.aspx is a good discussion of how to do this, from the PowerShell team blog).  It is often much more straightforward to write parts of your program in PowerShell.