With a sharp knife, some hot glue and a little creativity, you can turn sheets of inexpensive craft store foam into your very own wild and wacky hat. Goofy foam hats are great for helping make you the hit of your costume party and for ensuring that the Jumbotron cameras pan to you every time you're attending a stadium sports event. Older kids capable of working with a utility knife and craft cement under your supervision may enjoy this craft, but younger children should help only with the design process.
Creating a Headband Base
Use a flexible measuring tape to measure the circumference of your head, right where you'd like the bottom of your hat to sit.
Draw a rectangle on the craft foam, using a ruler to create straight, even edges. The rectangle should be as wide as the circumference measurement you just took, and as tall as you want the hat to be. To make a stovepipe hat or a silly-looking space-alien hat, make this "headband" 12 inches tall.
Spread contact cement on the short ends of the rectangle. Once the cement is dry, carefully press the ends together. They will adhere instantly, so take care to get the edges lined up correctly. If you don't like the all-or-nothing approach of that instant adhesion, you can use craft glue instead.
Double check that the "headband" you've just created sits comfortably on your head.
Finishing the Hat
Place the "headband" you just made on another sheet of craft foam and trace around it. Cut along the line you just made, using a craft knife so the cut-out circle remains intact.
Trace a foot-wide ring around the circle you just cut out; use butcher paper or cardboard as a template, if you need it, to make a perfect circle. Use your craft knife to cut out this ring as well.
Cement or glue the cut-out circle to the top of your hat base.
Slice a straight line through the ring. This will make it easier to neatly cement -- or glue -- the ring to the bottom of the hat base. Make sure to glue the split parts of the ring back together too; if they don't line up perfectly, they can be hidden by turning them to the back of the hat. If you stop now, you'll have a goofy, floppy-looking stovepipe hat. Keep going to turn it into a silly-looking space alien hat.
Trace around the top of the hat base onto four more sheets of craft foam. Cut out the circles inside the tracing and save them for a future project. Cut a 9-inch-wide ring from one sheet, a 6-inch-wide ring from another sheet and a 3-inch-wide ring from the last sheet of craft foam.
Split the rings, as you did with the largest ring, and glue or cement them onto the headband base at 3-inch intervals. Place the smallest ring 3 inches up from the biggest ring that you already glued in place. Add the next larger ring 3 inches above that, then glue the last ring to the very top of the hat. The result is a silly-looking hat that's reminiscent of the space aliens from old "Looney Tunes" cartoons.
If you're feeling really crafty, use markers to color the extra cut-out circles like planets and attach them to the rings on your space alien hat.
Other ideas for creating silly hats out of foam include cutting a large triangle out of foam and gluing the edges together to create a conical wizard's or witch's hat, or gluing long, pointy triangles to a headband base so they flop over and form a jester's hat.