I agree that for a 'games room' solar power is almost useless.
BUT, if your going to go down the 12V route, then your in luck.
My camper runs off a split charge 12V system into a leisure battery, which powers a bank of LED lighting, charges a notebook and also runs my DVD player and sound system. I can run for hours with everything turned on (I am no sparkie so cannot work out the a/h), I am planning to put two 80w panel's on the roof to keep it charged up when we go camping for longer then a weekend (although we do have 230V hook up, its nice to not have to be at a site and hooked up).
My friend runs a whole DJ set up from his camper (decks, laptop, mixer, amp & disco lights) from his system, he uses two 12V leisure batteries and he says that a 8 hour charge will give him two hours at full power (again two 80w panel's).
So if your planning LED lighting and low powered equipment, then no reason why not.
Remember you will need leisure batteries not just a 12V battery, also a charge controller otherwise you could fry your batteries.