Dan and Blair get it on in the elevator in "Con Heir." Watch their elevator sex scene in all its glory here.
Added:
Dan and Blair attempt to get it on in this clip from Monday's Gossip Girl, but it doesn't go as planned. Check it out.
Added:
Chuck and Jack discuss events in their lives in this clip from Monday's Gossip Girl, "Con Heir".
Added:
Blair gives Lola a lesson in this clip from "Cross Rhodes."
Added:

Gossip Girl Season 5 Quotes

Blair: I hope never giving up on people isn't going to be my downfall.
Chuck: That's why you're going to be an amazing mother. You're always there for the people you love. Even when they don't deserve it.
Blair: You know that's never going to change.
Chuck: It's okay if it has to. Starting tonight I'm going to take care of myself.
Blair: Is that all?
Chuck: Yeah.

Chuck: I'm sorry for losing my temper the night you told me Louis proposed to you. I'm sorry for not waiting longer at the Empire State Building. I'm sorry for treating you like property. I'm sorry I didn't tell you I loved you when I knew I did. Most of all I'm sorry I gave up on us when you never did.
Blair: Thank you.