Generic company sysadmin.

I have a rotating list of power user tips. I'll pick one to show someone during a trouble call (provided no one is in a huge hurry). It has to be something cool that I can demonstrate/teach in seconds. Examples:

Snipping tool. Rather than writing down error codes.

Windows key + start typing the program name. Rather than navigating the start menu.

Piles of excel tricks. (everyone loves excel)

The big thing is knowing your audience. People enjoy participating in something, not just being shown things they can never accomplish. If you make it something they can't understand it will just make them feel stupid or frustrated.