I'm a firm believer that sometimes the best solution to a simple problem is a simple answer. Instead of a fancy home automation-based solution, this Craftsman Auto Switch - Model 24031 solves the common need to turn on or off several pieces of equipment at the same time. For only $20.

(I also love that the top of the plug is covered in sawdust in the photo. Is that a nice bit of staging, or did they just snap a photo of one in-use?)

Thanks to Cool Tools for the link.