Doctor Who is one of the longest running TV shows on the BBC, and it's got a huge fandom surrounding it. Doctor Who fans, like other passionate fan cultures, create art & fan fiction and engage in a strong remix and cosplay culture. But it's more than that. Doctor Who provides a philosophy; a way of understanding the universe. Fans embrace this in ways that are similar to most world religions: a positive influence that changes their approach to daily life. Also, the Tardis makes a pretty great shrine!
(with thanks to Heath Fradkoff)