Goalball is a fast-paced team sport originally designed for blind athletes. It has been a part of the Paralympics since 1980. This inclusive game involves people with different degrees of visual impairment, so they all wear blindfolds so they're on even ground.
The players are divided into two teams with three players each, and additional substitutes. The court is a hardwood floor, like in a gym, on a rectangular court with a line in the middle and goals on both sides (like a soccer field).
The game is played with a ball that has bells embedded in it (so it can be detected through hearing). The objective is for each team to roll the ball across the other team's goal and defend their own goal.
The game is over after two 10 minute halves, and the winner is whoever scores the most goals.
If the ball is thrown out of bounds, possession goes to the team who did NOT touch it last. If, after a shot, the ball bounces off a defender or the goal post and crosses over the center line, possession goes to the team who just defended the shot.
A penalty shot is awarded when a team takes more than 10 seconds to throw (shoot) the ball, the same player takes three throws in a row, for unsportsmanlike conduct, and for distracting noise.
You can check out the International Blind Sport Federation for the official rules, or you can modify them so you and your friends can play using the resources you have. Definitely check out a video though. You really have to see it to get it.