I totally bought a 5 pack of eclipse glasses about a month ago on Amazon for $8 and have been thoroughly enjoying the frantic FB posts of people looking for Eclipse glasses 2 days before the event and shocked that when they find them they are getting ripped off. It's not like this is all anyone has been talking about for the entire summer or anything.
Well the Boy Scouts and my son's 6th grade science teacher have a solution for your last minute eclipse viewing needs.
1 shoebox, tinfoil, tape, a pin, white printer paper and a box cutter or xacto knife and your troubles are over.
Zero was supervising, of course.
Step 1. Cut a small hole (about 1 inch across) in one end of the shoe box, near an edge.
Step 2. Tape a piece of tinfoil over the hole.
Step 3. Using a pin or needle, punch a hole in the center of the foil.
Step 4. Tape a small piece of white paper to the inside of the box, at the opposite end from the foil-covered hole. The paper should be positioned so that light entering the box through the pin hole will hit it. This is where you'll look for the sun.
Step 5. Cut a 1-inch-diameter hole in the box near the image screen (the white piece of paper), but on a different side of the box — the side adjacent to the screen. This is your viewing hole; it must be positioned such that you can look through it at an angle and see the image screen.
When the time comes for the eclipse, hold the shoe box so that it lines up with its own shadow, demonstrating that it is aligned with light from the sun. Stand so that when you look through the viewing hole, you can see a tiny bead of light on the image screen; that's the sun. During the eclipse, you'll see the shadow of the moon pass in front of the sun.
You can see a video here