I see, but I’ve seen both in classical and popular (musical scores) notation, and it’s not that uncommon. I would say that outside piano lesson text books, I’ve come across 2/2 more often than the cut time symbol.
Yep, and that’s what surprised me.
Interestingly enough, the cut time/alla breve symbol can also represent 4/2 (as evidenced in some works of Brahms).
Actually, looking over some piano books, it seems the more modern works tend to the 2/2 notation, while the older ones tend to the cut time notation.
I’d agree. It’s pretty common.
The weirdest time signature I’ve had to deal with recently was 13/4.
Try 7/12!
Yikes. You win.
I can’t even figure out what that means. My musical education as a child was limited. Would that be seven dotted sixteenth notes per measure? Or what?
Perhaps it’s some weird rhythm based on tripletised quavers?
Yep - Wikipedia does have an entry on it, but I’m tempted to go and clean it up 
Time signature - Wikipedia