A proposed mission by the European Space Agency seeks to send a pair of spacecraft out to a nearby asteroid to test the effects of smashing one of the crafts into the asteroid at 6.25 km/second. The primary goal is to see how well a possible method of asteroid deflection would work, but it won't do anything as spectacular as actually blowing up the asteroid. I guess they're saving that honor for Bruce Willis.
The asteroid Apophis, clearly named for the Stargate SG-1 villain, has been called a "doomsday asteroid," because in 2004 there was a study that said there was a 2.7% chance of Apophis hitting Earth when it flies past us in 2029. That study has since been disproved, but astronomers are keeping a close eye on Apophis anyhow, which is due for another pass in 2036. One telescope in Europe has captured new images of Apophis that reveal it's even larger than initially believed. That can't be good.