Custom rifle manufacturer DoubleStar built this modified AK-47. Its most obvious feature is the chainsaw fixed to the barrel, powered by a lithium battery so you don't have to be attached to an outlet when the zombie apocalypse certainly most definitely happens. If Ash had this, Army of Darkness would be about half as long.
~Not-"Not-So-Handy Andy" Jack
Deviant Artist Midnight Angel put together an arm blade stylized after the ones used in the Assassin's Creed video game series. Using a drawer opening mechanism, a spring for a screen door, and a throwing knife, the weapon works surprisingly smoothly. The full instructions are on Angel's page, and you can see it in action below.
Okay, let's try to assemble a normal tent. The long pole goes into the socket with the other short pole, the other other short pole slides into the flux capacitor, then cast expecto patronum on the tent stakes, then divide by zero, and voila! You're done.
Now here's a tent that makes camping a little bit easier. The tent has a geodesic dome frame that inflates when you pump it full of air. Just inflate, and you're done!