9x09 "The One with Rachel's Phone Number"

On a girls night out with Phoebe, Rachel gives a guy her phone number, but instantly regrets it after realizing she would need to move on from Ross. Joey thinks Monica is having an affair when Chandler claims he needs to work, as he does not want to lie to Joey about wanting to spend time with Monica, rather than going to a game with him. While Phoebe and Rachel are out, Ross invites Mike to hang out, but as Mike doesn't want to talk about his divorce and Ross hasn't got his keyboards with him, they realize they have little in common.