I was sitting outside watching a show last night (about 8:30?), when I looked up at the sky and saw a point of light growing brighter and brighter, then slowly dim out to black. The point wasn't moving, and the whole process took less than 10 seconds. I believe I saw a nova/supernova! The location was directly below the North Star, about 10-15 degrees down towards the horizon (maybe a hands width at arms length). I can't believe I was the only one to have seen this, but I didn't see anything in the news about it. Do you have any info?
I'm sorry to say that you probably didn't see a nova or supernova. Supernova (when a star exploses) and nova (smaller explosions on the surface of a dead star) are visible for weeks, so it wouldn't brighten and dim within 10 seconds.
My guess is that you saw something closer to home. One possibility is an Iridium flare. There are Iridium communication satellites which occasionally are oriented so that they reflect a lot of light down to earth, making the satellite become many times brighter than normal for a few seconds. You can look up when one of these flares will be visible from your location.
http://www.heavens-above.com/ (This website also will tell you when other satellites like the ISS and Hubble will be visible)
Around 9:14 on Sept 2 there was and Iridium flare in the north that should have been visible to you. So that is my best guess at what you saw. However, normally one can tell that satellites are moving. Perhaps the short time that it was visible made it appear to be stationary.
I hope this helps clarify a little. Thanks for your question. -Katherine