Gossip Girl episode 6

Dan is between two girls when his childhood friend, Vanessa, returns home and declares her feelings for him, just as he and Serena are trying to figure out what they mean to each other. At the infamous masked ball, Blair sends Nate on a scavenger hunt, but Nate is ultimately still distracted by his feelings for Serena. Although Blair makes it perfectly clear that outsiders are not welcome, a disguised Jenny and Dan sneak into the ball. Jenny tells Chuck that he has to go hide and that she will find him by following his clothes, but then she locks Chuck in the roof in underwear.
 Finally, Lily asks Rufus to accompany her to an Eleanor Waldorf event in order to make Bart Bass jealous. And kissed, it works because Bart went to talk to her.