You’ve successfully tested the limits of how much can fit into a #10 envelope without bursting its seams, but now you’re questioning how much postage you need. Sure you could just slap a few of the new 44-cent stamps onto whatever you're sending and be done with it, but that’s good money you’re throwing away.

Instead, spend just a few bucks now to build a simple magnetic postage scale, newly updated from an original article in the February 1971 issue of Popular Science.

The retro-futuristic design of this skateboard was inspired by the look of rocket ships in old cartoons. Ryan Bavetta used a jigsaw to cut out the sleek deck and then mounted a propeller and 3.7-horsepower engine from a model airplane on the back to power it. A handheld remote controls the engine throttle, which can move the board 25 mph or more wherever he wants to go.

For all he's done and all he's taught you, you'd think dear old Dad would be honored more than one day out of the year. And if you want to get technical, had he not teamed up with mom on that one long-ago DIY project, you wouldn't be reading this right now. So this Father's Day, pay homage to his tinkering spirit with something he'll use in future acts of glorious creation.

Throughout this guide, you'll find a wide selection of tools from free iPhone apps to a budget-busting hammer drill; an oh-so-convenient cordless glue gun and soldering tool; plus a variety of things to help him amp up his environmentalism, his swing, his gut, and his chances of getting a speeding ticket.

To coincide with this year's Invention Awards, we've started the National School Inventors Challenge, a contest for students around the country to submit their world-changing ideas and inventions. Here, see engineering students at Miami Coral Park high school putting together plans for a solar-powered bike.

Our third updated DIY project from the Popular Science digital archives involves luring and then trapping bugs that have managed to find their way inside your house--a truly universal problem. Follow along as we update a circa-1971 trap for today's smarter, more intelligent insects for less than $20.