It appears you already have some great responses to your question as this is exactly what I was going to recommend as well (I always take the already referenced DVDs with me whenever I go on travel). If you have a DVD player (or a laptop that plays DVDs), I would also recommend taking Bootcamp. There's an option for doing just the cardio portion of this. True, it's really short, but if you only have a few minutes to spare, this is an awesome workout.
Lorrayne