I was just doing this workout yesterday and wondering the same thing! The song at the beginning of combo 5 is Rihanna's "Umbrella". The one I don't know (and really want to!) is the song that starts halfway through combo 5, starting at about the 35:30 minute mark. I always feel like the name is on the tip of my tongue, but I just can't quite place it. I hope someone can answer your question!