While browsing the SVH section at fanfiction.net, I found this hilarious parody fanfic with Margo in it. It hasn't been finished (and was started 2 years ago) but the chapters that are up are worth reading.
Check it out:
http://www.fanfiction.net/s/2386149/1/Margos_Great_Idea Also - I've been mulling over starting a Sweet Valley fanfic community here at Livejournal. Would anyone be interested in contributing, or would you know people who would contribute if I created such a community?