Im about to go the "country" (large peice of land my parents own), and I wanted to bring something that fires much like artillery. But anything that shoots (and homemade) would be great. Anyone has ideas?
I used to do this when I was little. The basic launcher can be made easily from copper plumbing pipe, and then the release is an old hockey stick or other suitable prying device.
Get a piece of PVC or ABS or other straight, rigid pipe that is just slightly larger than the diameter of a small CO2 cartridge, you know like for a pellet gun. Get a dowel rod or something similar that is exactly or slightly larger than the ID of the pipe. If it is larger, sand/lathe it down so it is snug. Drive a small diameter nail or brad through the dowel exactly in the center of it so that the sharp end protrudes. Insert this plug into the pipe, pointy end inside. Glue or drive a few small nails or screws into the base to keep the plug in.
Now all you do is drop it, maybe have to shove it with some force, down the tube, nozzle end down. Ideally the nail will puncture the seal on the CO2 cartridge causing all of the gas to be released in short order. This will launch the metal cartridge quite far.
Not quite as biodegradable as spud gun projectiles, but damn fun to see how far you can make them go with varying barrel angles.