How do I construct a mirror with a sensor and speakers?

I have this great idea for a Christmas present, but I don’t exactly know how to build it. I want to attach some sort of sensor and some speakers to a mirror. The idea would be that someone would walk up to the mirror thus alerting the sensor to their presence and then one of a couple of phrases would come through the speakers.

example: “Looooking Gooood!”

Any ideas on how to build this rig or where I could go to purchase kits?