wakeonwan is a Ruby command-line tool for waking your machine up remotely. If your router is configured to route Wake-on-WAN packets, and your machine has WoW enabled in the BIOS, you can wake your machine remotely by typing:
wakeonwan 1.2.3.4 11:22:33:44:55:66
where 1.2.3.4 is your public IP address, and 11:22:33:44:55:66 the MAC address of the machine to wake up.