I always seem to walk out of other people's classrooms learning something.
I observed one of our part-time faculty a few weeks ago (this is part of my responsibility as a faculty member), and she gave an example that I plan on using in the future.
One thing I always have trouble explaining to students is what type of RAM they need. The best answer I've been able to give is to consult the manufacturer's Web site, which is admittedly a pain in the rear end.
Crucial (a company that makes RAM) has made available for free a memory scanner. This program will tell you how much RAM you have, along with how many slots you have available. If you were considering a RAM upgrade, this is vital information, and this tool saves you having to open up the PC.