I happen to have received the CC3000 shield yesterday and have been playing with it today...
What do you mean by "receive commands from a website"?
There is an example sketch of an HTTP server included in the CC3000 library that would get you started. Note that the example HTTP server sketch can only handle one HTTP request/response at a time.
You will obviously also need some way of controlling a relay of you want to control a lamp.
Update: Since you updated your question to include how you are currently communicating:
I'm not familiar with socket.io or Firmata, but I'm guessing socket.io is a way of getting your web client (browser) to talk directly Firmata which talks to your Arduino over the USB-Serial connection? If so, then I'm not sure if it's possible to use the Firmata protocol over wireless, but it is possible for the CC3000 to act as a generic TCP server and act on data that it receives wirelessly, so it might be possible to communicate between socket.io and the TCP server. The EchoServer sketch shows how to set up a TCP server to receive raw data.
If you're only turning a lamp on/off you basically only need to control 1 pin. Isn't Firmata a bit overkill for that? Be careful about sketch size. I'm not sure how big Firmata compiles to, but the wireless library with some kind or server is over 22,000 byes (of a possible 32,000) on an Uno, so you might struggle to fit both on.