I often go on night hikes and geocache along the way. In fact, I spent a few hours doing that last night. I can't think of a more fun activity involving a flashlight. It's especially fun for flashaholics because geocaching at night is impossible without a flashlight (as if we need justification). I found all but one on the trail I was on last night and I spent a long time looking for the one I couldn't find. I'm almost convinced it's not at the listed location. Having geocached for a while, I have noticed some do get removed or misplaced.
For those who have a flashlight collection but don't necessary have a use other than to fire them up in the backyard, I strongly suggest nighttime geocaching. This is especially fun if you have kids. I introduced geocaching to a coworker with two small kids a while back and he told me his son and daughter love it. They were more into it than Pokemon Go. Not only is geocaching like a treasure hunt in the aspect of finding hidden stuff, the larger caches often have goodies for kids like stickers, themed erasers, pins, little toys, etc. However, as an adult male, I've found some neat things for myself like tent pegs, quick-release key rings, keychains, foreign coins, etc. The rule is if you take something, you exchange it with something you brought. It's a good way to get rid of any small knickknacks, stickers, or small items that are of no value to you but someone else may appreciate. The smaller "micro" geocaches are often just large enough only for a log scroll but they are still fun to find. Once in a while, you may come across an official geocache game piece. I found one two summers ago in Santa Clarita, CA and it was an Olympics themed piece. The goal of that game piece was to travel the world to Olympics-related sites. What's fun about these pieces is that you can track them with a code on them to see where they have been. I took the one I found and dropped it off at a geocache in Kona, HI when I was on vacation. I later tracked it and saw that it went to an Olympics training site in Colorado.
While I don't have any kids and often go night hiking and nighttime geocaching alone, I still enjoy it. However, given I'm alone and roaming around with a flashlight, I often go find the geocaches on trails and outdoor areas rather than residential areas that might have "muggles" (people who don't know about geocaching) who may get suspicious of my activities.
I think geocaching is easier than ever now. When I started back in 2006, you had to download the geocache points to a handheld GPS. Now, you can download the geocache app for free on your smartphone and use that to find geocaches. There are also way more geocaches out around the world than ten years ago. While the app does require payment to "unlock" certain features, it lists most geocache locations in the free mode. The green ones are listed for anyone while the grayed out ones show the location but any further info needs to be "unlocked" by payment. However, it's not often necessary given the location is shown on the app's map. I don't have a paid account and still found several grayed out geocaches last night simply by knowing their location on the app's map.
Again, if you're looking for something to do with your flashlight at night, this is a great activity. Here are some photos from last night's nighttime geocaching.