Joke

The Eleventh Doctor once included a joke and two diagrams with proof of faster-than-light travel to convince a body of geniuses they should take his advice about how to save the world from annihilation by the Atraxi. (TV: The Eleventh Hour)

Andy Hansen once told a joke to Erimem which involved R2-D2 in the punchline. (PROSE: Arrrr...)

A running joke between Lim and Mitch was that Lim kept her phone on all the time and was an instant replier. (TV: Resolution)

Bram and Gregor Van Baalen told their amnesiac brother Tricky he was an android as a joke to relieve their boredom. (TV: Journey to the Centre of the TARDIS)

The Fourth Doctor prevented an Ectoslime from killing him by telling it a joke in an alien tongue. He later tried to translate to joke to General Ironicus ("These three aliens walk into a bar, and the first alien says...") but was interrupted before he got to the punchline. (COMIC: Doctor Who and the Iron Legion)