The Bay Area Model's Guild holds model marathons during the year and they are so much fun.  It is six hours of usually 10 models at a time  in poses ranging from 1- 2 min gestures , 5 & 10 min, 20 min and one long pose (for people who actually bring paints) and is currently $40 for the whole day.  The model's are really good, very professional and range in body types which I love.  Additionally, if you like quick poses, usually by the end of the day the 1-2 minute poses usually end up being a group effort ranging from quirky fun to lovely lyrical compositions (incentive to nail those quick sketch skills during the rest of the year!)