Check the Quebec Games & Events section (here
), this is where public games are listed; there's a compiled schedule with additional information (including addresses and directions to the fields) stickied at the top of the section (link
Games at Action 500 occur every 2 weeks and are easy to get to (right in the city, near a subway): you'll be able to meet people, get age verified and check equipment out. Yuo can borrow a mask/goggles for free from the facility if you want to check out the field.
However note that this type of indoor skirmishing is substantially different from what is played outdoors at most events.
Gun rentals are sometimes possible at some games, but in my experience is pretty rare.