I'm trying not to get my hopes up too high, because 30 Rock already made my heart soar once this Fall and then went and smashed it into a million pieces. But! If this were to happen, it would be even more amazing than the Gossip Girl crossover: Jon Hamm is in talks to guest-star on 30 Rock as a potential love interest for Liz Lemon.
The plan, apparently, is for Hamm to be around for multiple episodes playing Liz's neighbor (and possible more-than-just-neighbor). That would put the lead actress from TV's best comedy (well, according to the Emmys, anyway) and the lead actor from TV's best drama together. On the same show! Possibly kissing!