What To Do With Spare Storage?

I had this idea, I have all these computers each with extra un-used storage space, an extra 100GB here, an extra 200GB there, but for what? just sitting around doing nothing, now if I want a network attached storage guess what? I need to purchase one and now I have that plus my spare 100 and 200 GB storage not being used.

What if I could virtualize the spare 100GB and the spare 200GB into either a 300GB stripped set or a 100GB mirroed partition and a 100GB regular partition? Now that would be cool.

I just found this link on Distributed File Systems