My buddies and I were trying to think of something we could build out of cardboard and duct tape. We came up with a tank. It was a little more costly than originally estimated, but it was fun and the end result is amazing. It'll blow your friends away! This instructable will go through each step in the process, and hopefully you'll be able to build your very own tank for you to play in (or your kids/pets/neighbors/neighbor's cat to play in).
BTW, please hit the vote button for the cardboard and duct tape contest!!!!
Step 1: Materials and Tools
For this job, all you really need is cardboard, duct tape (regular gray, dark gray, white, and black), and something to cut with (utility knife works great). We also used a few power tools along the way, just to speed the job up--they're not required. Also, get as much cardboard as you can get your hands on. We went to or called every appliance store in town begging for cardboard. Ask for fridge boxes, washer/dryer boxes, anything big works great. Also, be sure to ask for the extremely hard cardboard used to protect the corners of the appliances. These are a must in a first couple steps. And, as for the duct tape, I think we ended up using about 60 rolls.