208 was the registry number of an emergency evac jumpship in service to Starfleet in London, on Earth, in 2259. At that time, it was reported that 208 had been commandeered by Khan Noonien Singh following his bombing of the Kelvin Memorial Archive in London.
During a later senior staff meeting in the Daystrom Conference Room at Starfleet Headquarters in San Francisco, Spock wondered why Khan would have stolen the jumpship as it lacked a warp drive, making it unsuitable for an interstellar escape.
Piloting 208, Khan appeared outside of the meeting's windows whereupon he attacked and killed Admiral Pike and many others by using the jumpship's weaponry. James T. Kirk crippled the jumpship by jamming its intake port with fire safety equipment, as the ship had proven impervious to phaser rifle fire. Before the jumpship crashed, Khan managed to escape from it by transwarp beaming himself to Qo'noS using a portable transwarp beaming device. (Star Trek Into Darkness)
Concept artwork of 208 was illustrated by James Clyne.
A concept image of the vehicle, on Scott Chambliss' website, can be found here.