The kind of fun stuff most kids these days miss out on...blowing stuff up and making your own instruments of destruction.
I knew some guys who took a hollow driveshaft from a truck and cut the end off, and the interior diameter was enough to accommodate a 12 oz plastic soda bottle.
They would act like a two man mortar team, one guy would put dry ice chips into the bottle, put in some water, screw the cap on, and toss it into the bore, and the other guy would put various items in on top of it from a tennis ball, or another bottle completely filled with water.
It would shoot the thing hundreds of yards!
One of my own favorites was to take three tennis ball cans, remove both ends, tape them together with duct tape, then make a small touch hole with an ice pick. You could squirt in a little Ronson lighter fluid (though not enough for your dad to miss when filling his Zippo!) toss in a tennis ball, then light the touch hole...:)