This isn't something I'm really going to maintain much but I needed something to do this so I thought I'd share... It allows you to pick holidays from a list and it will turn a switch on on those days. Cobra originally had something similar but since he took his apps down, I threw one together quickly to meet my needs. It will also let you define some custom dates for things that aren't really holidays but you want the switch toggled anyway.
Like I said, I don't really intend to add any additional features to this, just needed something to meet my needs but I'd be happy to accept pull requests for enhancements from others.