Article: Babysitting Co-Op forecasts economic recession

I started a babysitting co-op for fellows and their families today. Each family starts with five "points." You can earn points by babysitting other fellows' kids, and you can spend these points on other fellows babysitting your kids.

#points = #kids * #hours

You can also earn points by hosting/attending playdates. 

The host of a playdate receives [#points = #hours * #kids that attended]. 

The parents who stay at the playdate with their kids can also earn [#points = #hours] that they participated in a playdate. 

Parents who drop off their kids and pick them up later spend [#points = #kids * 1/2*#hours] that they participated in the playdate.

This article, from a fellow fellow, details the reasons why the babysitting co-op failed. Originally run by congressional fellows (young, intelligent professionals), people started to hoard the "scrips" (or babysitting currency). So the scrips went out of circulation.
http://www.slate.com/articles/business/the_dismal_science/1998/08/babysitting_the_economy.html