Originally opened sometime around 1600.
Currently: If you're very very lucky, it's playing near you. Go see it! (And if you're not that lucky, check out the fantastic 1993 Kenneth Branagh movie or the equally brilliant 2012 Joss Whedon version. Just don't ask me to choose between them.)
Written by: Shakespeare.
Everyone knows about: They're tricked into falling in love. As well they should be.
I have thoughts: This is, without a doubt, far and above all else, my favourite play. I first saw the Branagh version when I was 15, which was the beginning of my lifelong crush on Robert Sean Leonard, even though I'd choose to be Beatrice over Hero any day. Also, Claudio is an idiot, no matter who is playing him.
Have you seen Much Ado? Actually, if you haven't, don't bother answering. Just pick a movie version and watch it. Now.