Basically a regular bowl with some netting on the top which, when you crack a nut inside it, the shell pieces don't fly everywhere and you don't have to use your hand to stop them either.
This is just a thing I got an idea for while I was cracking nuts. It's turning out to be very useful.
TAPE - Good duct tape, packing tape or other really grippy tape, that crap clear scotch tape crap won't work.
NETTING/PLASTIC BAG - Cover of the top, make sure it's strong.
ELASTIC - Also make sure this is reasonably strong.
Step 1: Cut the Netting
Cut the netting the right size to fit over the top of the bowl and some extra. Don't worry about it being circular. You need the corners kinda anyway.
Step 2: Put the Netting on the Bowl
Place the netting on the bowl, flip the bowl over onto its top and pull reasonably tight. Tape down the corners to keep it in place.
Step 3: Put the Elastic On
Pull the elastic over the bowl and make sure it's down real far. I highly recommend taping the elastic in place.
Step 4: Usage and Optional Making of Holes
To use it, find a hole in the side where the netting doesn't quite cover the bowl totally and put in your nut cracker and nut. Proceed with teh crushing ownage of the nut. If there is no hole to put the cracker through, cut a SLIT, not a circle or square one but MAKE IT SMALL as in like 3 centimeters. Otherwise the shell fragments will just fly out of the hole.