We've got the computing society who have a 24 hour gaming night on Fridays every week. You can play games on consoles / PC / handheld devices and more. They also have LAN parties and 1 week long gaming events. There's also the Warwick Game Design Society which is the place if you want to make games but they have having gaming evenings too like the computing society just for less hours. The only other I can think of is the Nintendo society.
You don't need to work about booking events as there are no limits on how many people can attend. You can just meet the societies at the Freshers fairs on Wednesday and Thursday of week 1