The answer to the question of whether Berlin is happy is closely related to the weather.
This phenomenon is probably true of most places in the world, but this little app is just for Berlin: http://isberlinhappy.jdenn.es
You can get the answer as JSON, by setting the Accept header value to application/json when making a request:
$ curl -H "Accept: application/json" http://isberlinhappy.jdenn.es
{"happy":"Yes!","text":"Fair","temp_c":23,"temp_f":73}
