If 'Grey's Anatomy' is gettitng a spin-off why not 'Desperate Housewives'? or 'My Name is Earl'? or 'Heroes'? Well, here are my personal kooky ideas.
"By Edie"
Edie goes off to her own adventures in Los Angeles where she has her own realty firm with sexy employees and competition. She gets to be bitchy with people in California.
"Heaven's Gate"
All those that have passed on such as Mrs. Huber, Rex, Mary Alice, and possible guest stars as the two former Mrs. Hodges and Zach's dead grand father. The plot? They have to go down to Earth as angels or devils to help people.
"Anything But Desperate On Campus"
Andrew Van De Camp, which is described by Wikipedia as 'Bree sociopathic, atheist, bisexual teenage son,' goes to college and becomes the dorm supervisor guy and has to put up with other people's problems and just scoff at their problems while finding love and causing trouble with nobody the wiser.