Oh dear, my brothers and I pulled so many shenanigans... it's a wonder we're still alive after a lot of them!
I used to sneak into the pantry and taste the spices. I also took a liking to powdered Tang.
One time when I was home alone I decided that it would be fun to light up a Christmas light bulb. So I plugged in the can opener, but only halfway so parts of the prongs were still showing. Then I spread apart the contacts on the Christmas light bulb and touched one to each of the prongs on the can opener plug. There was a loud bang and my fingers tingled really bad. After I calmed down a bit from the surprise I went back and looked for the parts of the exploded light bulb; there was nothing anywhere. I think the bulb disintegrated.
My little brother used to call the operator from every pay phone he could get to. He would ask stupid questions like "Where does Darth Maul live?" in a high-pitched kid voice, and he'd always get told that he should ask a parent before using the phone.

We never did tell our parents, but we nearly got caught one time when he decided to call 911 from a local grocery store.

We were at the checkout and he and I went out to the pay phone and he said he was going to call 911. I told him not to, but he did and when he was asked where he was he said "HERE!". Of course, the call was traced and the grocery store got a call and were asked if anyone called 911 from that location. An employee was walking around asking if anyone had called 911, and of course my brother and I said no. We left just a few minutes before the police got there, and I know they had security cameras pointed at the phone. I'm just amazed that we were not sought out and arrested!
We also used to do "daredevil" stunts when our parents weren't home. These included jumping from the first floor balcony into couch pillows, climbing on top of the metal shed and sliding down, and others, but my favorite was the "roller coasters". Our basement was full of stacks and stacks of boxes, plus plastic pantries, a standup freezer, bookshelves, and lots of other tall things. We would tie wire shelf pieces together with twist-ties and set them up on various levels of boxes, starting on top of the freezer and sloping down. Then we'd get in a laundry basket, have a sibling give us a shove, and go on down the "track".

Some of our coasters got pretty elaborate, too! One time we just did a straight drop by placing "track" down the very steep basement stairs. I think the ending was the worst.

I'm still amazed that none of us got hurt!