Some faves:

Decorate your dom/me's leathers with oil painted neon polka dots and stripes

Place a whoopee cushion on your dom/me's favorite chair.

When getting flogged, start singing 'This is the song that never ends...'

Have a wig made up matching your hair color and style perfectly. It'll be worth the expense to see the look on your dom/me's face the next time your hair gets tugged and it comes off..

Attach clappers to all the outlets in the dungeon just before a paddling. (Clap on, clap off...)

Put up flyers around town, advertising that master is missing, answers to Pookie, reward for his safe return.

http://members.aol.com/alkallah/samhints.html

Now, this was on a straight ref, however, it can apply to gay masters-slaves, and is worth the laugh!
:p