Here’s a set of holiday themed contest entries:
With a home automation system already in place, and considering the time of year, [Thom] chose to use his Christmas tree lights as the contest easter egg. When he uses his smart phone to set the fifth channel of the lighting controller to a 50% duty cycle it causes the string of lights to mete out the Hackaday web address as a series of dots and dashes. You can find the code here (DOC).
[Jacques] offers up a flickering LED as the host of his hidden easter egg. When you short the two leads of the LED for a little bit it forces the PIC 10F200 into a different mode that then flashes our URL in Morse Code. Have a look at the assembly file. His implementation was based on the reverse engineering we saw recently.