I have yet to participate in one, but apparently a person starts it by forming a list of people to ship the chips to. The originator sends out x number of chips, typically some theme ($1 non-LV, snappers, etc.) is in the RR. The chips then go from person to person, with each person taking the chips they want and replacing them with chips from their collection. The chips eventually wind their way back to the originator, and they have the fun of seeing what was added to the collection.

Sounds like a lot of fun, and I look forward to taking part in one.