Control

Try dropping it again. Seriously. Inside the remote there is a very small 'gyro sensor' that can get stuck in one spot, basically all you have to do is jar it loose again.
I actually had this same thing happen a while ago, I called Nintendo customer support.
I was surprised. A very pleasant lady took my call within one minute of getting through the push-button maze to get to Wii Remote troubleshooting.
I explained what the problem was and what I had tried. She then asked me to check one more thing - the Wii Sensor - which checked out. Then the conversation went something like this:
Friendly Nintendo Help Desk Lady: "Okay - I want you to take the remote, button side down and smack it into the palm of your hand two or three times."
Me: "You've got to be kidding"
Friendly Nintendo Help Desk Lady: "No sir, do it hard enough that I can hear it across the phone line but not hard enough to damage the remote"
Me: "You're sure?"
Friendly Nintendo Help Desk Lady: "Yes, sir."
So, button-side down, the funky Wii remote got smacked in the palm of my hand three times....
...and the thing worked!