Update: I have since built the $16 nRF24 wireless serial controlled light switch and the ESP8266 based WiFi to nRF24 bridge. Please see the above links for project write-up.
I made a serially controlled light switch by combining a $3 servo, a $4 Arduino Uno and an old laptop...
I used some mounting tape and hot glue to keep the servo on the switch plate, and the servo stays in neutral position when not activated so the light switch (decora style) can be operated by hand for ease of use.
I've got a Wi-Fi shield on the way and I plan on getting rid of the laptop and will probably re-write the sketch at that point... Stay Tuned for more details and pictures!!