The Doctor's moped

The Doctor's Moped was a small, blue Vespa motor-scooter that the Tenth Doctor kept in the Tardis, along with appropriate helmets.

He and Rose Tyler rode around on the moped when they thought they were going to see Elvis Presley perform. Instead they found themselves in London in 1953, but their clothes and the moped did not look out of place. (DW: The Idiot's Lantern)