For this instructable you will need:
A Red Bull can or just can bottom
Tin Snips or Scissors
Pliers (Preferably long-nosed pliers)
Like 3 minutes...
Step 1: Cut the Bottom End Off of a Can
Further trim this edge so that the circle is even all the way round. This will keep the disk balanced.
Step 2: Bend the Edges
Bend the edge down so that it follows the curvature of the dome. Once you have done this, bend it more inward " <__> "
Then, simply clamp the edge down to touch dome. Follow this through evenly for the entire rim. Fix any "unbalanced looking" edges so that the finished product is as circular as possible.
Step 3: Using It
The key to the Frisbee's stability is in its spinning motion. Forward motion should follow naturally but getting enough spin is necessary to get some good flight from this small disk. To provide lift as the object moves through the air it is convex on the top and concave underneath. The reason for the edge being the heaviest part is simple, the outermost edge of a rotor (rotating mass, not just a blade) will be the fastest-moving part. By this being heavier it retains momentum better and has a stabilizing effect too because the edge is also the lowest part of the Frisbee, thus giving it a low centre of mass (sort of like a parachute).
Throwing it is all about a sort of flick of the wrist to give maximum spin. I hope the last 3 pictures show in enough detail how a flying disk should be thrown to get adequate spinning momentum.