Jon Favreau
After Swingers but before he directed films like Elf, Chef and Iron Man, Jon Favreau played Monica's super-rich husband who wants to become an Ultimate Fighting Champion.
Aisha Tyler
Aisha Tyler played Charlie, the paleontologist who dates both Joey and Ross. But neither proves smart enough for her: She prefers Nobel prize winners. After Friends, Tyler went on to star in 24 and now voices Lana Kane on Archer.
Paul Rudd
Sure, Monica and Chandler were a great couple, and the will-they-or-won't-they drama of Ross and Rachel was endlessly entertaining. But the best pairing on the show was Phoebe and Mike, played by an utterly lovable Paul Rudd. Rudd has had perhaps the most successful career of the Friends vets: Anchorman premiered the same year that Friends wrapped, and the comedian quickly shot to superstardom with The 40-Year-Old Virgin, Knocked Up, Role Models and I Love You, Man.
Cole Sprouse
You know that kid who played Ross' son (that he barely ever saw) Ben? He went on to star as Cody in the Disney Channel's The Suite Life of Zack & Cody.
Michael Rapaport
Before his roles in The 6th Day, Hitch and The Heat, Michael Rapaport was Pheobe's cop boyfriend, who she had to break up with after he shot a bird.
Rebecca Romijn
Before she was Mystique in the X-Men movies, Rebeca Romijn baffled the Friends by dating Ross despite being super hot. (Though too be fair, the Rachel-Ross combination never really made sense either.) But Ross ultimately breaks up with the girl because her apartment is filthy and has rodents living in it.
Steve Zahn
Best known for roles in Sahara and Dallas Buyers Club, Zahn first played Phoebe's gay ex-husband and ice dancer in an early episode of Friends.
Tate Donovan
In the 1990s, Tate Donovan was probably best known as Jennifer Anniston's real-life boyfriend. They played an onscreen couple too: Rachel goes to great lengths, even donning her old cheerleading outfit from high school, to win the affection of Joshua. Donovan went on to stints on The O.C. as Jimmy Cooper, Damages as Tom Shayes and 24: Live Another Day as Mark Boudreau as well as roles in films like Good Night, and Good Luck and Argo.