Neat list!
1090kHz makes plane spotting so much fun. You can see where they are hundreds of miles away with a smartphone/computer and a cheap rtl-sdr. A 900 meg patch antenna works great really but a good random wire thrown into a tree...
There are a few cheap and free things and some very expensive ones. Some are outright dangerous, but look like great fun. I've wanted to base jump or even skydive but never have. I think I'd like like it. If have to remember it's not a dream where I go splat again though. I've done a lot of those things at different times. I'm a big nerd, so mostly the ones in that vein. I wanna go find somebody to wrestle with now... Not to win, but cuddle with afterwards.