Chums
Chums was a television show.
The Tenth Doctor sometimes watched it with Rose-the-cat. (COMIC: A Rose by Any Other Name)
Behind the scenes
Chums is a reference in two-fold. First, it is a blatant parody of Friends. Second, it is actually a parody of Friends which was first mentioned in an episode of the NBC series 30 Rock. The implication of the segment was that it was a British remake of the show, with characters such as 'Russ'. The show Glee also did a similar joke, but the references in the comic make it more clearly inspired by the joke in 30 Rock. In real life there was a show called Saturday Morning TV: Live (or SMTV Live for short) in the early 2000's that featured a parody of Friends that went by the same name.