My understanding that the easily recognized "Happy Birthday" tune is in public domain. Does anyone know if there is a version of this that is very slow and mellow, without words, that is or can be looped?
The "Happy Birthday" song is actually still protected by copyright which is why so many restaurant chains come up with really annoying alternate versions: no royalties.
I'm not sure when the copyright expires, but at the rate our elected officials are voting for the highest dollar, it may get extended yet again.
In any case, there's a page at snopes.com that covers the song's history and current status.
That's not to say that you won't be able to find a MIDI file of it somewhere - it is the most sung song in the world, after all, and royalty fees are normally collected from large commercial entities such as films and restaurants.