Actually, I keep a light on by my bed in my room during the day. The reason is that my room is often very, very messy, and with no light on, I cannot guarantee that I will make it across the room from the door (where the light switch is) to my bed uninjured if the sun has gone down.
Technically there is a light on in my room for a few seconds after I turn that one out, for an odd reason.
I am a pretty frequent user of the chain type craft stores (like Michael's Jo-Ann etc.) and an inveterate comber of their glass bead section. Over the last few months, my local Jo-Ann's has been doing a sort of clearance of one of their suppliers (I don't have a package on my, but it is called something like Bead Designer or the like. which supplies small bags of mixed beads of a selected nature (as opposed to the larger units I buy there, which are random groupings). In some of these packets recently have been a glass bead design that has surprised me two ways.
The first was the discovery that the beads, which I originally took for basic spiky balls (all of the others beads in the mixes are very geometric, stylized shapes) are in fact caricatures of pigs (the "spikes" are the ears, legs, snout and tail, and there are two black dot's on each one for eyes.) (rather out of place with all of the other designs, so I think they may not have thought that selection out very well.
The second is what happened the night after I pulled them out and had left them by my bed under the lamp (which, as I said is on all day) Come night, when I turned it off to go to sleep, suddenly there was a pile of little green stars! Turns out the little white crumbs inside of them glow in the dark! I've seen this once before (with an apple shaped bead I found in a bulk mixture) I think they do it with a kind of powder (the standard methods probably wouldn't work, as most of them would burn if they came in contact with molten glass.) But in any now for about ten minutes after I turn off the light, I have a constellation in my room (the apple, which I still have is even brighter, I can read my watch by the light from that.)