The Mars Phoenix spacecraft is scheduled to land this evening in the northern pole regions on the red planet in the further pursuit of water and previous life. The Science Channel will have live coverage starting at 4pm PDT. Other local stations will probably have coverage just before the actual landing.
Other info at: http://mars.jpl.nasa.gov/missions/present/phoenix.html
Other info at: http://mars.jpl.nasa.gov/missions/present/phoenix.html