The Wheels On The Bus
From Tardis Wiki, the free Doctor Who reference
"The Wheels On The Bus" was a song. The Seventh Doctor once led a bus full of passengers in a rendition of the song. (PROSE: How You Get There)
The Eleventh Doctor cited the following slightly modified passage from the song on the Great Wheel, the mothership of the Amstrons, "The wheel on the bus goes round and round." (COMIC: The Eternal Dogfight)