I know nothing about hockey, what makes it 'East Side' hockey?
Eastside Hockey is a style of hockey like Rugby is a 'style' of Football.
Basically it's like regular Ice Hockey you normally see, except they play on a smaller field and have seven players on the ice at any time, split evenly between the two teams. Instead of a puck they use a small ball made of leather or something. The sticks are different too, resembling grass hockey sticks but not as thick (think shaped like a candy cane). You are actually allowed to use the stick to 'trip' the opponent as well, so long as you don't strike them.
The object of the game is to 'lose' points, so you try to score 'own goals' while the other team has to stop you. And score more own goals.