Feliz is the site of the annual "Festival do Chopp" -- a gigantic festival of draft beer with a German theme. It's kind of like Octoberfest, but in Brazil :-)
I can't really say that I got to know Mossoró very well, since I had a layover at the bus station at 2am... Kind of a creepy place to be stranded at late at night, I have to say.
Tel Aviv is a great, fun city. Lots of stuff to do, good nightlife, and a cool beachfront vibe during the summer.