A hydrogen vent leak prevented Endeavour from being fueled up last night, so the Shuttle launch had to be delayed. It's quite a delay, too: the next window is on July 11! This is due to a geometric angle problem; during this time of year the Shuttle and Space Station would be at an angle to the Sun that makes thermal issues a problem. So they have to wait a month to try again.
In the meantime, some real science will get underway with the launch of the Lunar Reconnaissance Orbiter tomorrow, Thursday, June 18. There are three launch opportunities all within 20 minutes of each other, starting at 17:12 Eastern time (21:12 GMT). I'll be watching, and live-tweeting the event on my BANews Twitter feed.
LRO will take several days to get to the Moon, but once there, and after its shake-down, it'll return wonderful data of our satellite, including images with details as small as 50 cm (18 inches)! I cannot wait to see those. Wow.