The 68 was a bus that went to Bolton.
In the early 21st century, the Ninth Doctor hijacked the 68, dressed in a bus driver's uniform, despite the protests of the actual driver. The Doctor drove the bus a quarter of a mile, arrived at a bus stop, and then ordered every passenger off the bus, except for a tall woman wearing something like a sari. The Doctor then drove down Lancaster Rd, which wasn't part of the bus's normal route.
One of the passengers, Joanne Marsden, complained to the bus company, but they denied knowing about the Doctor or even the incident itself. Joanne later wrote about her encounter with the Doctor on whoisdoctorwho.co.uk in March 2005. (PROSE: Have You Seen This Man?)