What is ultimate exactly? Is that a shorter name for ultimate Frisbee or something? 
Yes that's correct, ultimate frisbee  is a non-contact team sport played by players with a flying disc 
I've noticed that the ultimate frisbees are a lot heavier and are made of different material than regular frisbees.
I'm not sure about that by I can tell you that the sport have been on since 1968 and was developed by high school students
1968? Wow that has been around for quite a while for such a modern sport.
Yes and also it's just like every other sport out there because it focuses on self-officiating, even at the highest levels of competition.
It really surprises me that high school students developed such a big sport!
Yes it is, let me tell you how the scores are gotten in ultimate, it is by  passing the disc to a teammate in the opposing end zone.