Good cardio exercise

In march I went on a skiing holiday and lost about 1-2 stone, but ever since then I've been feeling really sluggish and hungry all the time, and my weight has been yoyo-ing between 48 and 53 kgs which is slightly irrating as I want to get a good healthty steady weight and in less than 4 days I'll be on holiday for 7 weeks which is the perfect oppurtunity to start a workout reigeme. I heard cardio was good so joined the gym but now I want to know what classes or outdoor activities that will burn off calories and fat but I can keep going all the way through out the year.

Ok, so if they offer like a tae-bo class, you can really lose a lot of weight. My class did a tae-bo session and I lost around 3 lbs! in a half an hour!

Thats amazing! what is tae-bo though?