From the Wii Troubleshooting section:
Check for interference from infra-red light sources, such as candles, sunlight, fireplaces, and stoves.
Radio frequency interference may cause the Wii Remote to work erratically. Check for wireless devices such as cordless phones, wireless computer keyboards or mice, or other similar devices, and move or turn them off.
The Wii manual also has a lovely photo with the Wii covered by a blanket looking oh so cozy. Of course the manual says that is a no no.
Move:
The motion controller may not be detected correctly if it is used in a location where the lighting is too bright or if it is exposed to direct sunlight.
Check that the motion controller is not being used or placed near magnetic sources.
When using the motion controller, avoid holding the controller closer than 20 cm from the face or eyes.
Its libraries that sell systems not a single game.
