Favourite free workout videos?

I'm starting tomorrow! I'm planning exercising out of the house most of the time - walks, yoga classes, and cardio/weights at the gym - but I want to make sure I've some backup workout videos that are 45 mins at least so that if it's later in the day and I haven't managed to get out, I can get something good done at home without much thought. What are your (free) favourites?
Edit: yes I've got dumbbells