Pimp #1 - fall_for_sx, created by claudia6913 to celebrate the goodness that is the Spike/Xander pairing. I've grabbed the Hallowe'en slot but there are many many open slots just waiting to be filled with goodies!
Pimp #2 - winter_of_wes, created by txrabbit and kyrieane to celebrate all things Wesley Wyndam-Pryce. I know they've already got some talented people signed up over there but there are still many slots open.
So, if one or both of these float your boat or inspire you to great feats of creativity, go, sign up and have fun! ;o)