I've just reached 3k reputation today and earned the close and reopen votes privilege.
Before I had this privilege, I was able to flag many questions as Blatantly off-topic, if they had nothing to do with videogames or didn't have their own off-topic reason (e.g. modded Minecraft tech support).
(Meta.SE flagging reason)
This produces a close reason like the following:
Today I stumbled upon a question that was titled something along the lines of 'Why 1+1=5' and contained some absurdly wrong mathematical theory in the body. Naturally I would have closed it as blatantly off-topic, because it obviously has nothing to do with videogames.
However there is no off-topic reason. The closest appropriate selection would have been the 'Other' option, where I would have left a comment along the lines of
I'm voting to close this question as off-topic because it has nothing to do with videogames.
How can I vote to close as blatantly off-topic?