I also teach Linux and in today's class I had everyone download the ubuntu 10.04
ISO image, burn it to a DVD-R that they can take home and also save the
downloaded image in their computer and create a new VM using it (we already have
VMs with ubuntu 9.10). Well there seems to be a bug in the VM using 10.04; it
creates it fine but when you first log in the keyboard is ignored...until you
use the accessibility option to enable the onscreen keyboard and use it to enter
your password...then you need to restart the VM