First appearance of Janine. In The One with the Princess Leia Fantasy (1996), Chandler mentions Elle Macpherson as one of the mental images that pops in his head during sex.
The big plate which Monica gives Rachel in The One Where Ross Hugs Rachel (1999) is shown on the dining table in Rachel and Phoebe's apartment.
The Magna Doodle has a 4x4 truck high-centered on small hill with two muscular stick figure men are on opposite ends of the truck and in giant letters "OOPS!" is written above it all.