Make CO2 Ice Cream

Cost: $150
Time: 15 Minutes

Safe | | | | |
Risky

For an illustrated photo how-to, launch the gallery.

If you're anything like us, you were the type of kid who took apart dad's
new radio just to see what was inside. That kind of curiosity never dies,
which is why How 2.0, PopSci's award-winning home for the coolest
tips, tricks, hacks and do-it-yourself projects, wants to see what today's
tech tinkerers are up to.

Have you built something amazing you'd like to
show off? Tried a How 2.0 project and failed miserably? Blown something up
with the kids' chemistry set? If you've invented it, tweaked it, hacked it,

Want some real home theater bragging rights? Instead of buying a projector capable of casting a 14-foot image at 1080p (progressive) resolution—the highest high-definition there is—build one yourself. After all, the front projector’s innards are simple: an LCD lit by a superbright lamp, and a few lenses to magnify and sharpen the image. Retail models start at around $800 and use proprietary $400 lamps that burn out every few years. But cheaper lamps work equally well, and none of the other parts are very expensive. Why not put one together yourself?