Best way to go is to keep an eye on the Ontario Games/Events thread.
You'll find a bunch in there and the season should really pick up soon.
Eventually you'll see three types of games...
1. Really unstructured skirmish games. Typically just show up, split into groups, blast at each other until everyone's dead...reload and repeat. No specific camo patterns/gear requirements, no ammo restrictions, etc... Just show up with eyepro + gun and you're good to go. Typically sound like, "hey guys, anyone wanna shoot this Friday" sort of thing.
2. Skirmish games. Usually you sign up for a team...usually separated by camo pattern. There's often ammo limits or at least a limit of highcap mags (the bottomless wind up mags). The games are usually set with a bit more of a structure in that there's an objective (one team defends, one attacks....or move this guy/thing from here to there...or get from here to there, etc...). There's often a number of sets throughout the day/evening. Some are light fun...others get a bit more serious.
3. "MilSims". Definitely a team and command structure. Defined objectives. Usually load ammo limits. Almost always there's uniform/camo requirements...sometimes load out requirements. They can be short-day....or multi day. Prep-planning can be from just a hour or so in advance to 6+ months in advance with workup training, etc...
I tend to avoid Type 1...just not interesting for me, but they can be a lot of fun. No muss/fuss.
Type 2 are fun and a great way to see if what you've got works. You won't always get the chance to spend 2 hours creeping into position to get that perfect shot...the games/sets usually don't last that long (but some do).
Type 3 offer a lot of organizational/strategy/tactics stimulation. Usually lots of action but often lots of quieter times too (which some guys don't like).