In-jokes and obscure references: Rachel references Jane Pauley from Dateline NBC (1992) as the only woman she'd ever kiss while helping Ross getting his couch upstairs to his apartment. Jane Pauley has twins (a boy and a girl) born in 1983 named Ross and Rachel.
A target is drawn on the Magna-Doodle after Phoebe finds a police badge.
Phoebe references Andy Sipowicz from NYPD Blue (1993) when she's talking to Gary outside Central Perk. Michael Rappaport, who plays Gary, guest starred in Season 1, Episode 3 of NYPD Blue. David Schwimmer appeared as Josh Goldstein in 4 episodes of NYPD Blue.
The Magna-Doodle says "Joey, Your Agent Called."
David Schwimmer and Michael Rapaport appeared together in the film The Pallbearer.