Or issue one-week tickets. I've been to a couple of places that do that - amazing if you have kids and they go off on one (ie have a bad day/meltdown), you can leave and not lose out.

Depends a lot on the venue, but some places that won't increase visitor stays, it might even reduce them. I'll bet it makes them nicer places to be too.

I imagine it wouldn't work for them Louvre!