Have you any idea how great they are as singers?? Hehe.....really! They're great singers!!!!! They sometimes even do Acapella!!^______^ Wanna know when did they sing?!? Okey, first of all, just so you know that three of the gang DID have singing background!! You know who they are?? CHANDLER AND ROSS!!!!! Yep! Ross love to make his own music, he even have a band and Chandler is the lead singer of the band in college!!! COOL!!! And, of course Phoebe.....she's a singer, country singer! You all know that! Okey, here they are :

[Ross working on crossword puzzle, suddenly he starts humming the theme from "The Odd Couple". Chandler joins in, followed by Monica & Phoebe, then the whole gang. When they're finish, Ross starts humming theme from "I Dream Of Jeannie"]
CHANDLER: No no no no, we're done.
Season 1, Ep. 12 ~The One With the Dozen Lasagnes~

ROSS: Hey, hey buddy, Marcel. Marcel. [Marcel doesn't react so Ross starts singing] In the jungle, the mighty jungle the lion sleeps tonight. [no reaction from Marcel, Monica and Joey urge him on] In the jungle, the mighty jungle the lion sleeps tonight. [Marcel looks over and everyone joins in] a-weema-way, a-weema-way.....
[Marcel runs over and hops up on Ross's shoulder]
Season 2, Ep. 12 ~TOW Superbowl (Part 1)~

PHOEBE: [singing] Smelly cat, smell-ly cat, what are they feeding you? Everybody!
ALL: Smelly cat, smell-ly cat, it's not your fault.
PHOEBE: Monica!
MONICA: [sings] They won't take you to the vet.
PHOEBE: Chandler!
CHANDLER: [reluctantly sings]..................you're obviously not their favorite pet.
MONICA: Joey!
JOEY: [sings] It may not be a bed of roses.
PHOEBE: Rachel!
RACHEL: [sings] And you're no friend to those with noses.
PHOEBE: Uh, Ross, those are the only lines we have, sorry. OK, you guys, once more!
Season 2, Ep. 17 ~The One Where Eddie Moves In~

[Scene: Chandler and Joey's, Chandler is listening to a Lionel Richie album]
Chandler: (singing) ‘I’ll hold you close in my arms. (Phoebe enters) I can’t resist your charms. And love....’
Phoebe: (joining him) ‘Love....’
Chandler and Phoebe: ‘I’ll be a fool for you. I’m sure, you know I don’t mind.’
Chandler: (high pitched) ‘No, you know I don’t mind.’
Chandler and Phoebe: ‘Yes! You mean the world, the world to me. Oh..’
Chandler: ‘I know.’
Phoebe: ‘I know.’
Chandler: ‘I’ve found.’
Phoebe: ‘I’ve found....’
Chandler and Phoebe: ‘...in you, my endless (Phoebe goes high pitched, Chandler goes low pitched) love.’ (they both look at each other.) ‘My endless love.’ (once again they don’t match tones, and they just look at each other)
Season 3, Ep. 8 ~The One With The Giant Poking Device~