I been searching around for a good Wii gun but allot that you can buy are expensive and the ones you can make look odd. So I made a template you can cut out and if you know how to work with adobe suit you could also color it in the colors or with the graphics you want.
Download the pdf , edit pdf and print it out. Then get the the materials you want to use.
Edit the PDF in Illustrator with the colors or graphics that you want. Also you could make it look even more like a real gun. Also print the grip of the gun few times out so you get the best size for you or the kids.
Print it out on normal paper.
Past it and a cardboard and cut it out. Best is to use cereal boxes because those cardboard got a big flat surface compared to other packaging and also it is totally free. It cheaper than to buy a big sheet of cardboard.
You could also laminate the printed sheet so it is water resistant but then you don't have to past it on a piece of cardboard because laminated sheets make it strong inof.
I paste it on acrylate sheet and then remove the printed sheet.
Don't forget to use a empty pen to follow the fold lines so it is easier to fold.