Wifi parabolic signal booster
: Fold some foil into a parabolic dish to boost your wifi signal from your router. Sure, it's unsightly and kind of goofy, but sometimes you need to be able to watch videos of kittens falling down stairs when you're nearly out of wifi range. There are some plans for this project right here on Instructables. Here's one
Photography light reflector
: Taking photos for my Instructables is always a chore. I hate that I have to wait for the light to be right at the office or at home, so I could really use one of those big light reflecting thingamajigs* that real photographers use. With some aluminum foil layered over a piece of cardboard, properly-lit pictures are just a light source away.
Fix loose batteries
: Sometimes the springs that hold batteries in place loose their springiness. With their springiness compromised, battery-powered devices might not work at all, or only work if you hold them in a certain position. (I'm looking at you, Comcast remote control that I had to hold vertically in order to DVR Real Housewives of Albuquerque.) With a folded up piece of aluminum foil, you can force those batteries back into place. Just fold up a little piece and wedge it into position so that the battery terminals line up correctly. This trick will blow the mind of a child whose Furby is acting up.
Protect your brain waves from eavesdropping and mind control
: Your thoughts are private. The government and super-advanced alien races (especially considering that they are probably in cahoots) shouldn't be able to read or control those thoughts. To combat telepathic control techniques that rely upon radio waves, you can fashion a protective helmet out of aluminum foil. Berkeley engineers have tested the wave-blocking power of aluminum foil and discovered that an aluminum foil deflector beanie actually magnifies extraneous signals beamed into a subject's head at certain frequencies. Probably propaganda. (You can see their results here
and decide for yourself.)
*Technical term, obviously.