Anyone can tryout... as long as you're a a Hufflepuffian and have a broom!
Here's The Positions RIght Now:
And if you don't know what Quidditch is.... *PFFFTTT*..... here is a definition:
"Quidditch is a wizarding sport played on broomsticks. It is the most popular game among wizards and witches, and, according to Rubeus Hagrid, the equivalent to Muggles' passion for football.
The game is played by two teams of seven people (three Chasers, two Beaters, one Keeper, and one Seeker) and involves four balls (a Quaffle, two Bludgers, and a Golden Snitch).
The Keeper guards the goal posts, while the three Chasers score goals with the Quaffle by tossing it into one of the opposing team's three goal posts. The two Beaters keep the Bludgers away from their team and hit the Bludgers towards the opposing team, and the Seeker catches the Golden Snitch to end the game. The team whose Seeker catches the Snitch is awarded 150 points, but this does not necessarily mean they will win if the other team still has more points than the other team before the Snitch is caught.
The object of the game is to score more points than your opponents. Each goal is worth ten points and catching the Snitch is worth one-hundred fifty points. The game ends when the Snitch is caught or an agreement is reached between the captains of both teams. Some games can go on for many days if the Snitch is not caught (the record, according to Quidditch Through the Ages, is six months)." - Harry Potter Wiki
P.S. YES, I'm not a Hufflepuff. But whatever!