Yo-yo

A yo-yo was a round toy which shot up and down on a string.

While at the Time Lord Academy, the Doctor would skip classes to practice yo-yos and juggling. (PDA: Match of the Day)

The Doctor gave Mindy Voir a yo-yo in exchange for signing his copy of one of her albums. (CC: Helicon Prime)

The Doctor, realising that the Time Lords had programmed his TARDIS to always return to Earth, compared himself to "some kind of a galactic yo-yo". (DW: The Claws of Axos)

The Doctor's fourth persona was the one who most frequently kept a yo-yo on his person. Although he once used it to test local gravity (DW: The Ark in Space), he apparently used it primarily for fun. His skill with the yo-yo appeared to increase over time. (DW: The Android Invasion, The Brain of Morbius)

Leela spun the Doctor's yo-yo, thinking that it was part of the TARDIS' magic. (DW: The Robots of Death)

On Silurian Earth, a yo-yo was found in the cloak pockets on the Doctor's body. (NA: Blood Heat)

It took Ace two weeks and tons of peer pressure to learn to use a yo-yo. (NA: Love and War)

Appearances of the Doctor's yo-yos

 * NA: Timewyrm: Apocalypse
 * PDA: The Murder Game
 * DW: The Ark in Space
 * DW: Genesis of the Daleks
 * DW: Revenge of the Cybermen
 * DW: The Brain of Morbius
 * DW: The Seeds of Doom
 * DW: The Masque of Mandragora
 * DW: The Robots of Death
 * DW: The Talons of Weng-Chiang
 * MA: The Romance of Crime
 * MA: The Well-Mannered War
 * MA: Burning Heart
 * ST: Special Weapons
 * PDA: The Hollow Men
 * PDA: The Algebra of Ice
 * NA: The Pit
 * NA: Sky Pirates!
 * NA: Head Games
 * NA: The Death of Art
 * DW: Doctor Who
 * ST: The Time Lord's Story
 * EDA: Frontier Worlds
 * EDA: Coldheart
 * EDA: The Space Age
 * EDA: Escape Velocity
 * EDA: Dark Progeny
 * EDA: The City of the Dead
 * NSA: The Price of Paradise
 * IDW: Fugitive