Season 1: Episode 11: The One With Mrs. Bing
Monica and Phoebe start flirting with a really cute guy as he crosses the street. Just as they catch his eye, he gets hit by an ambulance. The guy winds up in a coma, and the two girls begin a "relationship" with their cute "coma guy" as he lays in the hospital. Chandler's famous, trashy novelist, party-down, sexy mom comes for a visit and winds up kissing Ross.