Find someone running a CheerLights and then ask Alexa to change the colour. This skill will send a tweet to Twitter changing the colour to that requested. The tweets appear under the Twitter account https://twitter.com/EchoCheerlights

You need a CheerLights device, for details how to build one see:
http://cheerlights.com/build/

Alternatively you can install one of the CheerLights apps:
http://cheerlights.com/apps/