Step 1: What You'll Need:
2 or 4 Bludgers: Dodge Balls
1 Snitch: A Golf ball.
6 Goals: PVC hoops attached to a wood or PVC pole works great.
The Quidditch Pitch: a football or soccer field, or make an actual Pitch.
7 players per team:
2 Outside Chasers
Blind Side Beater
Open Side Beater
Optional: matching uniforms and padding.
Step 2: The Game Balls
Bludgers- These are used to tag out the the opposing team's Chasers. These are typically small iron balls, but for these I suggest using dodge balls. These are bigger and softer than real Bludgers, but they get the trick done. If you want to you can also spray paint these brown, grey, or dark blue. The Beaters will hold and throw these themselves, since they have no means of traveling by themselves. You can use only 2 Bludgers, or you can have 4: 1 for each Beater.
The Golden Snitch- This is the ball that determines the end of the game. If caught, the game ends and whichever team's seeker has possession of the Snitch wins. For this one, you have a few options: either use a golf ball painted green to blend into the grass, or use a bouncy ball and only release it a few times in the game (I'll explain later), or you can use a person as the snitch and release them a few times. It's up to you, unless you've got a real magic flying gold ball.
Step 3: The Players
The Three Chasers- They run up and down the pitch passing the Quaffle by hand amongst themselves, in an attempt to score goals by throwing it through one of their opponent's three goal hoops (Explained Later). In this respect It's is similar to rugby, or, as Harry suggests in the first book, "basketball on broomsticks with six hoops".
The Keeper- Charged with protecting the three goal hoops, in much the same way as a goalkeeper in soccer.
The Two Beaters- Throw their own Bludgers towards opponents or protect their teammates from the opposing Bludgers by knocking the balls off course.
The Seeker- Depending on your Snitch of choice your Seeker will have a slightly different job.
1. If you use a Green Golf Ball, before the players come onto the field hide the ball as you would an easter egg. It's painted green to make it harder to spot in the field.
2. If you use a bouncy ball, the referee will release the snitch at some point in the game. The snitch needs to move as much as possible, which is why a super-bouncy ball is needed. If the snitch stops rolling or bouncing without being picked up, it goes back to the referee to be released again later in the game.
3. If you use a person, make sure they are dressed in a separate color then either team (Gold would be ideal... and make him wear wings in his head for fun!). The Idea is similar to the bouncy ball. The Snitch is released at some point in the game and runs as fast as he can away from both seekers until he is tackled by one of them. If he is not caught by either in less than say 30 seconds then he sits on the side until released again.
Step 4: The Quidditch Pitch
The Goal Areas need to be similar to a large half circle at each end of the Pitch. The Keeper cannot go outside this area and the Chasers cannot come inside. Inside these Goal Areas are three hoop-shaped goals near the end of the field. For this ground-based version, I recommend making the center hoop to be about 10 feet high and and the two and each side be about 6 feet high. I included some pictures of the goals so you can get an idea of a couple ways to put the goal hoops together (though in one they are playing with Frisbees)
In the center of the pitch is a circle and center line that acts as a starting point similar to that in Basketball. The referee releases the Quaffle from this spot.
Step 5: Game Play
The Beaters cannot cross the center line. Their goal is to tag the chasers with Bludgers. If a chaser is hit, he must stay planted where he is and has 3 seconds to pass the Quaffle to another Chaser.
Capturing the Snitch earns the Seeker's team 150 points, equivalent to 15 goals scored by Chasers. Since the game ends immediately after the Snitch is caught, the team capturing the Snitch is very likely to win the game. However, teams are ranked according to points scored, not games won. Games are best played 2 out of 3 and the team with the most points at the end of the tournament wins.
It is a foul if anyone but the Seeker touches the Snitch. If anyone touches the Snitch, all players must leave the field, the referee re-hides the Snitch, and the team who fouled looses 30 points.
The Quaffle must be surrendered to the opposition if any player leaves the boundary.
Time out may be called at any time by a team Captain. It may be extended to two hours if a game has already lasted for more than twelve hours. Failure to return to the pitch afterward disqualifies the offending team.
The referee can impose penalties if a foul occurs. A single Chaser from the fouled team takes a penalty shot. The opposing team's Keeper may attempt to block this shot, but no other player may interfere.
Contact is allowed, but a player may not grasp any part of the opposition's body, this is a foul.
No substitution of a player is allowed, even if one is too badly hurt to continue
Blagging: No player may seize any part of an opponent to slow or hinder the player.
Blatching: No player may run at someone with the intent to collide.
Bumphing: Beaters must not hit Bludgers towards spectators or the Keeper unless the Quaffle is within the scoring area.
Cobbing: Players must not use their elbows against opponents.
Flacking: Keepers must not defend the posts from behind by punching Quaffles out of the hoops goals must be defended from the front.