Two possible suitable asteroids for a manned mission: 1991 VG and 1990 AO10

The names of those two asteroids come from an article here, a nice lengthy writeup on the push by some to send a manned mission to a near-Earth asteroid. The idea of sending people to an asteroid often tends to get lost in the discussions on the ISS, Moon and Mars, but may be worth doing especially if a suitable asteroid presents itself. The two asteroids mentioned in the title could be visited in 2017 and 2015, but we are still a very long ways away from knowing about each and every possible near-Earth asteroid so at the moment it's still best to just keep discovering and cataloging them. Next month's WISE telescope will be a huge help there.

Personally I'm now of the opinion that it's not worth expending any resources on anything other than the Moon, but you never know when the perfect asteroid candidate will be discovered.