Rules for a "short to medium length" game?
I have no idea if any of these are "universally accepted", as I haven't consulted with the rest of the universe, but I have seen a few variations on ending the game.


A large number of people I've played with don't like getting back to the center for the final question, because you're basically holding out for a lucky roll to get back to the middle.  Instead, once you have your sixth pie wedge, you immediately are asked the final question; if you don't answer correctly, on successive turns you get another final question, no moving required.
If we want a shorter game, we've altered the number of pieces required to win, anywhere from 4-6.  It's been pretty satisfactory for us.


If you want to make things a little more interesting to prevent people from avoiding their least-favorite category, we'll sometimes randomly select one of the six color wedges from a pile -- you must have this piece in your collection to win.

I'm not a fan of a time limit, because slower players can make the game end prematurely by (intentionally or not) dragging out the clock.