Most of the crazy stuff I've done involves pyro, but there are plenty of other crazy (or just stupid) things as well. Most of this was in my teenage years.
1. Friends and I used to go "paintballing" which involved shooting houses, buildings, cars, etc (NOT people). Not very smart considering you could get in serious trouble for it. Accidently broke someone's window doing it too, which got a police blotter entry. Kinda surprised me since we were >50ft away.
2. Built potato guns and also shot stuff we shouldn't have. There's still a street sign down near my house with a big dent in it...
3. Spray painted a stop sign entirely green with the word "GO" in white... surprisingly, it was replaced the next day.
4. Building a homemade firecracker... in my bedroom... was sealing it with candle wax and accidently caught the fuse with the flame. Ran around my room for a few seconds going "oh crap, oh crap, oh crap", ran out of the room to the stairs and threw it toward the foyer which had marble tile floors where it landed and immediately, BOOM! It left a big scorch mark on the tile and luckily it wiped clean, but I then had to vent all the smoke out of the house before parents came home.
5. Made some DIY "AP", thought I'd put a small pile of it in a small glass "pomade" jar that had a wide open top. Well, the stuff ignited and proceeded to instantly shatter the jar into little glass fragments that went flying at high speed, one of which ended up embedded in my ear (and not my eye!). Yeah, no more glass containers for explosives for me.
6. Modified a firework rocket (the kind with fins that stands on its own) with 30g flash powder. Worked fine in previous attempts, but the wind must have had its way with this one because it was only 30ft off the ground when it made a 90 degree turn TOWARD MY NEIGHBORS HOUSE! The weight also slowed down the lift off and it ended up delaying it enough that it exploded right over the tree between our houses. Otherwise, I don't think the neighbor would have been very happy with me.
7. This year, close call with fireworks. Setting off some of the small shells that you buy at the store. Timer fuse must have been defective or something because when my brother and I lit off one each, we only were about 10ft away when mine decided to explode only about 5ft off the ground. Scared the crap out of us as the burning crackling stars went flying past us and left our ears ringing from the report. Little more cautious about the rest of them.
I'm sure there are plenty more, but enough for now