The human eye is far more sensitive than the fastest film. So what often looks like a glaring beacon to us is not seen by any film.
Glaring beacon doesn't begin to describe some of the gear I have, and I can't easily turn it off.

Initially the brightest thing in there when I turn the lights off is the glow-in-the-dark part of the control box for the Enlarger, but the longer I'm in there the more I notice things. I spent 10 minutes or so in there tonight with the lights off, I was able to walk around without any problem. The most depressing part was the amount of light getting through the poster board. I just ran up to Dollar Tree for foil and other stuff. Unfortunately the darkest shower curtains were only dark blue, but they should help some.
Be careful covering some indicator lights as they serve a useful function to warn us of problems. Sure you could remove the covering each time but what of that time when you forget and something goes wrong. Would you cover over the check engine light on you car?
I'm thinking more and more about covering up the FIOS LED's. I didn't even know the one LED existed until tonight. It's not like I'm going to look at them unless there is a problem, at which point I can pull the electrical tape. The amount of light it puts out is insane!
I would not cover any electronic equipment with a box, you run the risk of the device overheating.
This is a real concern for my Wireless router. I'm making sure there is air around it, but not really sure what to do with it. Unplugging it isn't a good option, but I might be able to move it into the house.