Keep the Peeps from your Christmass stockings and use them to measure the speed of light with your kitchen microwave.
The speed is calculated if you know the frequency, from your microwave's information label (or manual), and you find out the wavelength. Because the wavelength is typically much shorter than a pyrex baking dish filled with Peeps, you can measure it. See how in this video.
Merry Christmass and happy holidays, all of them.
Yes.... after the Peeps cool down you can eat them. ;)