Does anyone have any recommendations for a good at home workout DVD program? I'm just looking for something to use on those days when the weather isn't so great or I'd just rather stay inside. I'd prefer that over spending a monthly fee at a gym. I'm looking for something that will give a good cardio workout with possible strength-training benefits. Kickboxing possibly, but I'm open to suggestions. I could go for a good mix of DVDs to help prevent boredom. I'd prefer something low to medium impact. I had ACL-replacement surgery after a ski accident a few years ago, and while the doctor says arthritis in that knee is inevitable in about 30 years, I'd like to try and stave it off as long as possible. Thanks, in advance!