Scheduling jobs on PCs after work hours

Hi All,

There's a task that I want to do and while I can explain it to people, I 
was having trouble finding the right keywords that would lead me home 
with Google.

Basically, we have 20 PCs in the office and we'd like to do some 
simulation/ test runs/ builds, etc. when CPU capacity is available.  
When there is an urgent demand, we reach "for the clouds", so to speak.  
But right now, we are just keen to use spare CPU cycles to do some 
random testing.

So, what I'm looking for is something similar to SETI@Home and does this:
* Wake up at a pre-scheduled time (say, after office hours)
* Connect to a central job server (and optionally present credentials)
* Ask the job server for a job
* Download the necessary for the job
 > this may include updating the local executable for the job
 > this may include copying a bunch of input files/ basic data
 > this will include copying data specific for this job
* Set up the environment for the job - copy the executable to the 
correct place, set up the data in the correct place and input files
* Call a batch file to run the job
* Once done, send the results to a central server and email the job owner
* Ask for the next job

Is there any ready-made solution that would let me do this, or would 
push me in the correct direction?  The client needs to run on Windows PC 
since that's what we have lying around in the office.

If there's nothing, could you point me to the kind of technologies that 
I should look at... this just might be a year-end hobby project :)

Thanks,
Mohit.