Season finale spoilers
Gossip Girl releases an email during graduation ceremony, (Chuck's a coward, Nate's a wh*re lol, Serena's officially irrelevant etc)
The gang tries to find out the identity of Gossip Girl, does not succeed (except for catching a guy who managed to hack into GG's server, giving them access to emails and secrets sent)
Hmm after trying AGAIN and failing to get Chuck to say "I love you" during the graduation party, he finally says it to Blair at the end (but not before going to Europe to pick up some gifts for her).. very cute scene
Serena apparently hired a private investigator to help find her father and receives news of his whereabouts (can't remember exactly, maybe Fiji or something)
Nate asks to go backpacking around Europe with Vanessa (as friends, unless they get drunk in Vienna) and she agrees..
In the same scene (coffee shop), we are introduced to......... Serena and Dan's half-brother! (He looks like Rufus (dark hair) with Serena's facial features hahah.. not bad) He is seen calling his mother and telling her how great NY is.. as he is looking at a newspaper featuring Rufus and Lily. Dan chats him up a bit, completely oblivious.
Jenny is crowned new Queen B
Rufus and Lily get engaged
Georgina manages to get Dan's Yale money back (even though he's going to NYU). Georgina says she'll see him there. She's seen at the registrar office requesting Blair Waldorf to be her room mates, as they're such "best friends"
That's the gist of it...