Two bloggers pointed out a couple of things that I found interesting.
Lynn Allen mentioned the undocumented FILTERS command. This command brings up a dialog box (with no help button) that allows you to pick which layer filters you wish to keep or delete.
Ralph Grabowski pointed out that if an onject is on a locked layer will display the icon of a lock when you attempt to select it.
Ralph also mentioned that if you hold the shift key while doing a fillet or chamfer the software will do a radius 0 corner. I like that very much.