The am335x ARM chip in the BeagleBone Black has a Real Time Clock hidden inside that you can use to have the board spontaneously turn itself on anytime in the next 100 years.

Here I present a new utility to manage that built-in clock from the Linux command line, and explain how to use it to keep time, shutdown, software power cycle, and more!

tldr;
Type these commands on your BBB running Debian and wait for about 10 seconds. You should see itself turn off… and then magically turn back on one minute later….”

Link