The contest of who knows the other person better with Chandler-Joey against Rachel-Monica is hilarious. The actors are in comedic high form. Sometimes the reactions and facial expressions are over the top, but the basic enthusiasm and competitiveness that arises from this "contest" makes it work.
Some subtle high points:
1. Chandler jumping up and down like the giddy, overanxious Chandler that we all know and love, during the lightning round.
2. "What was Monica's nickname when she was a field hockie goalie?" "Big fat goalie." And Monica's great expression after that answer.
3. How Ross waits a second longer to build suspense and allow the audience to digest the answer, before revealing whether the answers are correct.
4. "It's Ms. Chanandler Bong" How Chandler self-deprecates himself just to one up the girls.
5. Joey's favorite food: sandwiches. (Any kind, all kinds, doesn't matter)
6. "ooooooo...that's interesting" When Rachel suddenly buys into the new stakes for the contest.
7. "What is Chandler's job?" Too boring for the other Friend's to even care about or remember. A nice, subversive dig on "serious" mainstream culture.
8. "Beep." "Noooooooo...." No extra dialogue. Just the final beep, and Monica's anguished scream.