Ground and wall skipping: If you throw the Frisbee with enough force and the proper angle it can skip across a brickcement wall or hard ground several times before it finally reaches the person you are throwing it to.
Solo catch: If you find yourself bored with nobody else to join you then you can throw to yourself. This is done by throwing the disc up into the air at a 45 degree angle. If you measure the angle and wind just right then it will come back to you. A word of caution though. The higher you throw it the faster it will come back at you. I gave myself a black eye once when I got overzealous.
Mid air separation: This works best if you have at least two people on either side of the toss. If you have two Frisbees and one is slightly large than the other then you can stuff the smaller one under the bigger one and throw them both at the same time. Sometimes the two will have separation anxiety, but other times they split off into two different directions in mid air.
Wobbles: If you pack a tiny bit of mud into the rim on one side of the Frisbee and then throw it the Frisbee will wobble as it spins.
Non-Dominant hand throw: If you get to the point where you think you are really good at throwing the Frisbee then try throwing it with the hand you don’t normally throw with. Unless you are ambidextrous, this can make you feel like a beginner all over again.
Juggling: Two people have a catch with two Frisbees at the same time. This creates the added challenge of trying not to throw the discs into each other, and it also doubles the speed of the volley.
Finally, at the end of the Day:
One other advantage to the Frisbee shape is that they are easy to find storage places for. They can be easily stacked on top of each other and you don’t have to worry about them rolling around. Another option is to designate a wall in your house as the disc wall and hang as many as you want on thumbtacks.