I don't know if this has been brought up around here before, but the B612 foundation is planning to launch an infrared space telescope into a venus-like orbit around 2017. It will be able to detect nearly every earth-crossing rock larger than 150 meters wide, and a significant fraction down to a few at 30ish meters. The infrared optics looking outwards makes it much easier to see the warm rocks against the black of space without interference from the sun and would quickly increase the number of known near earth objects by two orders of magnitude.

This is exactly the mission I've been wishing / occasionally agitating for NASA to get off their behinds and do for five years. They've got the contract with Ball Aerospace to build the spacecraft and plan to launch on a Falcon 9 rocket. And they accept donations.