The absolute BEST genre of music out there. It is unappreciated by idiots who think the only music worth listening to is rock and rap. It's also the best music to play if you're a musician, because playing music is the only activity that involves every part of your brain, and jazz does this to an extent. It's also really fun to play and listen to.
If you're not sure if you like jazz, go and pick up a Basie or Ellington album and you'll see what I mean.