The rules are simple. The first poster starts with a random pair of two words (Must work together, they can't be randomly put togther like Unicorn Toothbrush. Unicorn's Toothbrush, however, would work). The next poster comes up with a new phrase starting with the second word of the last one. You can change tense, if it's singular or plural, etc, as long as the base word is the same.
Example:
1: Microsoft Windows
2: Window Blinds
3: Blind Mice
I'll start.
Chocolate Frogs.