Vesta may have been melted 4.5 mya and it is believed to once have volcanic activity.[1] Smaller asteroids may have deposited carbon material to Vesta, contrasting its bright color.[1]
Vesta doesn't have enough gravity to form it into a complete sphere, which is why it is not a dwarf planet.
The Dawn spacecraft has visited Vesta as one of its objectives.
Main belt comet P/2010 A2. Its base is 140 meters across.
These are comets that are within the asteroid belt. Only a handful of main belt asteroids have been discovered. It is uncertain what causes these objects to have a trail, but this event only occurs for a few days at a time.[2]
