Ah yes, how could I forget Aminet. Set up one machine with a browser pointing to it.
I'd also suggest a machine loaded with all the possible strange and cool handlers there are. Things like FTP:, HTTP:, compression directory overlays, that editor I never remember that you could read the open files from directly through a handler etc.
Datatypes should be showing somewhere. That is something that I think nobody except Be has tried properly.
Bootable/loadable filesystems. One machine should be jammed full of all the filesystems you can find (hm, you'll hit the limit on the number of disk RDBs you have) and mount.