Ideas for newbies who want to learn how to machine

A thought ocurred to me while machining today - squaring up stock takes a significant amount of time. I figure a good training exercise for mill work would be to have newbies attempt to square up a piece of stock to some standard dimension (like 3x3x0.5, whatever will fit in the scrap stock). Maybe the HSC could even sell pre-squared stock for a small fee, since it's a big convenience.

Could also do something similar for lathework.