If you’re a morning person, or at least don’t mind getting up really early to see something really cool, you should try to catch the Perseid meteor shower at its peak. The meteor shower, which started back on July 17, will be coming at its most frequent tonight and early tomorrow morning, meaning that the best time to watch for them is between about 1:30-2:00am local time, when the moon sets, and dawn.
The Perseids come every year at about this time, when the Earth passes through the trail of debris left by the comet Swift-Tuttle. If you can get to a place where there’s not too much ambient light, they’re a really good show, sending shooting stars out of the constellation Perseus (which is where the meteor shower gets its name).
If you don’t feel like getting up that early, you can get a pretty good show starting at about 9:00pm tonight, but they’ll be much more frequent in the early morning (and the sky will be much darker, without the moon, too). Information on where to look for the meteors can be found here.