If Youtube videos do not play reload the page, that's a Youtube bug.
Or maybe now, a few years later, it's a new bug ;-)

Ania Printcez and The Amateurs - The Belief

Cœur de pirate - Francis

Cœur de pirate - Place de la République et Adieu (Wood & Wires Session)

Mika Ben-Yami - Nothing is Wrong

Lisa Hannigan - Knots