Most recently - the discovery that the centaur (icy asteroids orbiting out past Saturn) Chariklo not only has two rings, but most likely a moon.
And the asteroid that sprouted six tails, each pointing in a different direction.
Astronomers think light pressure spun it faster and faster - the so-called YORP Effect - until after millions of years it's now spinning fast enough that loose gravel is being flung out into space. It may is be the way small rubble-pile asteroids die. See this swarm, discovered in September. It's currently gracefully flying apart.
And off course the bizarre debris from a deep-space collision back in 2010
Quite a few asteroids are oddly shaped, as well. eg: Astronomers Bounce Radar Off Monster Space Peanut