I want to post a question about the game Towns, but there's no tag for that game and I can't create one. I'm not really sure if any tag that current exists applies.
How can I post this question; what tag(s) should I use?
Tag it with anything else that's relevant. (Platform tags, such as pc or wii are a good choice here). Hell, feel free to tag it with something irrelevant but valid that will attract attention. It doesn't really matter, just give it any damn tag. Step two is the important part anyway:
Then flag it for mod attention, or bother any of the dozens of high rep users in chat to get the tag fixed nearly immediately.