In the Hitchhiker's Guide to the Galaxy text adventure, once I'm on the Vogon ship, how can I get the Babel fish in my ear? The darn thing keeps slipping away!
Take off your gown, and hang it up on the hook. Then, get the towel and put it over the drain. Wait until Ford is asleep, then nick his satchel and put it in front of the panel. Put the junk mail on the satchel, then press the dispenser button.
(From the FAQ which is full of spoilers. I consider it ruining the fun to use the walkthroughs, but in the Real Old Days, you could get an Invisiclues clue-book that you used an invisible-ink marker with. Boy that was cool.)