Cardio
The best way to burn some calories is to get a good cardio workout, like HIIT training.
HIIT will also strengthen your heart and give you plenty of energy. There are several activities you can do to get a good HIIT workout, and you should try different things until you find a workout you really enjoy. You could also go running, swimming, ride your bike, learn a martial art or dance. Your local gym probably has different classes you could join to learn kickboxing, do some aerobics or dance.