Today, there are 2 forms of boomerangs, War and sport. I believe the War one is more
difficult to use, while the Sport one is meant for
novices. They can stay in the air for a really long time, I've heard 4 minutes for some pros.
There are various models:
Albatros
Carlota
Fuzzy
Ikarus
Standard
Triller
Erics Fast Catch
You can learn how to make your own at http://www.rediboom.com/englisch/bauplane/index.html
From the Boomerang FAQ at usba.org:
Were boomerangs used for hunting?
No. Returning boomerangs aren't heavy enough to kill anything bigger than a large insect. In Australia, where the returning boomerang probably originated, boomerangs may have been used as decoys to mimic birds of prey, tricking a flock of ducks into the waiting nets of the hunters.
And the history of the boomerang, which dates back to prehistoric times:
Aerodynamic throwsticks were developed by Stone Age civilizations in different parts of the world as long as 15,000 years ago. The Australian aborigines are
the best known; however, these special hunting weapons were also developed in other areas including ancient Egypt, the American Southwest, and eastern Europe. While there are many stories of how the returning boomerang came to be (many rooted in myth and misinterpretation), most anthropologists agree that it originated from the throwstick.
The throwstick, called a kylie by the native Australians and a rabbit stick by the Hopi people of pre-European America, was a heavy, non-returning aerodynamic weapon thrown horizontally to kill or stun prey. At some point (perhaps by accident) the stick became more curved and refined (and much lighter) so that, when thrown vertically, it would return to the thrower. These true boomerangs were probably only used for fun and games, not as weapons.