Now that we're in public beta, you need 150 rep to create a new tag.
We recommend that any question that's specific to a particular game should have that game's name as a tag.
If you're a new user and you ask a question about a game that's never been mentioned before, then you can't create the tag for that game - @matiash had this problem here with trivial pursuit.
Can I suggest that we have a tag for "Game that doesn't have a tag yet and I don't have enough rep to create one" so that 200+ users (500+ when we go live) can easily spot these questions and retag them. Any suggestions of a good name for that tag?