The Fish Doorbell.

Just in case you're looking for an excuse to look at a soothing murky green screen... you are helping fish?

There's a boat lock in Utrecht that is closed during spring - but that is the time of year that fish migrate upstream for spawning. The city has found a rather ingenious solution: The Fish Doorbell. You can watch the livestream from a camera in front of the lock, and when you see a fish, you can ring the doorbell for the fish. Once enough fish are waiting, the lock is opened and they can travel on.

You can find the doorbell here (even with an English version for the site). It's just the right thing to watch when you need to look at more or less nothing for a bit. And if you're lucky, you might see a fish!