The last NASA Space Shuttle ever, STS-135 Atlantis, is set to launch today at 11:26 am EST. This is a very historic event, and I urge everyone to tune in and watch. I know there are a lot of political things that can be said one way or the other in regards to this being the last mission, but please don't say them here.
Again, I urge you to tune in (though there is currently only a 30% chance of it happening today), there are many places to watch it. The link below is probably the easiest