In this Instructable, I will show you how to control things powered by 110V AC with an audio signal. This project was inspired by a similar one done by Alan Parekh on a different site, but I have made some revisions (not all on purpose) and the instructions here will be much more inclusive. Please be careful. Unplug first when working on anything electrical. 110V AC can kill you!
http://www.instructables.com/id/Audio-Controlled-Christmas-Light-Flasher-With-Indi/