One of my favorite asteroids is Kleopatra: a big, 217 km (135 mile) long main-belt rock that's a wee bit weird. This image may give you a hint as to why:
It's shaped like a cartoon dog bone! It circles the Sun out past Mars, tumbling end-over-end, and its origins have always been something of a mystery. However, new observations and analysis reveal quite a bit about how this asteroid got its unusual shape. I won't spoil it, but instead simply point you to Emily Lakdawalla's excellent summary of Kleopatra on The Planetary Society blog. It's a tale of collisions, spin, and eventual reconciliation, as many good stories are.
One thing I didn't know is that Kleo has two moons: Alexhelios and Cleoselene. They orbit the asteroid in the plane of the its rotation, and may be cast-offs from the formation of Kleo itself. Read Emily's article for the whole scoop.
Man, the solar system is a cool place. And there's still so much left to see!