Unicycle

The Eleventh Doctor was skilled at riding a unicycle. He once participated in Le Tour de Parisian Dix, a unicycling race on a lava planet, and won the race for the eleventh time. The Doctor joined the race to help a Galactic Marshal catch a dangerous criminal. (COMIC: Le Tour de Death)

The Seventh Doctor and Ace once encountered a man who was juggling several balls while on a unicycle. (PROSE: One Card for the Curious)