During the poker game, most of Fred's hand is shown 7,8,5, Ace, & 6 all in diamonds which is a flush. After Fred's fiance heads upstairs everyone asks about her to which Fred replies that he'll tell them all about it after Joel plays his turn. Joel takes a card & ends up with a full house. A flush beats a full house in poker by 1 as a flush's rank is 5 & a full house's rank is 4.
As Sam & Joel are walking into the recital Joel says it's like a classy night out at the Met then Sam says they're in a middle school. The scene just before they walked into the school there was an outside shot of the building & the sign says Manhattan High School.