It's a lot like darts. Aussie Round is similar to Accuracy, but you have to catch it. You get points for distance, making the catch, and how close you are to the bull's eye when you make the catch. Fast Catch is just as it sounds. You are timed for how long it takes for you to make 5 catches.
Endurance is perhaps the most tiring.
It is actually a fast catch that lasts for 5 minutes. You get points for the number of catches you make in those 5min. The record is 76, which is the average number of throws a baseball pitcher makes in an entire game, but this is done in 5min. Trick Catch is making a series of difficult catches ranging from one handed catches, behind the back, under the leg, and with the feet. Doubling is the same as Trick Catch, but you throw 2 boomerangs at once, and must make an assigned trick catch for each one.