How do you make a projectile using specific materials?

For physics I have to make a projectile that completes a distance and accuracy test. For the base of the projectile I am allowed to use any materials as long as the it is freestanding. For the launcher I am only allowed to use 2 standard paper towel tubes, 10 popsicle sticks, up to 10 rubberbands (max length unstretched 10cm), 5 paperclips(max length 5cm), tape and/or glue, and 8x8 corrugated cardboard. The projectile will be a standard ping pong ball. The purpose of the distance contest is to make the ping pong ball go as far as possible. The purpose of the accuracy contest is to make the pingpong go a certain distance that will not be known untill time of testing. I have no prior experience with building so I have no clue as to even where to start! Any help at all would be VERY VERY appreciated!! Thanks =)