Possible Duplicates:
How to show popup message like in stackoverflow
Header message just like at Stack Overflow
How to display a message on screen without refreshing like SO does?
I'm looking for something like StackOverflow's banner that pops up (or rather drops down) from the top of the screen when you have a new alert. Preferably some javascript widget, though I'd be open to anything that will work with an ASP.Net MVC2 web page. All I'm looking for is a simple top-banner alert/message that looks good, preferably with a cancel button. Is there something like that, freely available?