If you've slacked off on the weekend, don't worry: you can still start your week right by burning 500 calories today. Do a variation of these activities every day this week, and by the end, you'll have burned a pound's worth (3,500) of calories!

One hundred at a time: Busy day? Break up your workout with these ways to burn 100 calories in 10 minutes, like jump-roping for 10 minutes or hopping on the elliptical at the gym during lunch. Yoga flow: Energize in the morning without coffee by taking a power yoga class before work; you'll burn 594 calories in just an hour and feel ready to take on your day. On the treadmill: This interval treadmill workout will burn 511 calories in less than an hour. Take it easy: A 10-minute circuit workout in the morning, a few minutes of jumping rope while you're watching TV in the evening, and a few more minute-long workouts in between — this plan for burning 500 calories in a day makes it manageable. Cardio class: Have fun, de-stress, and practice your moves in a dance or aerobic class after work. A Zumba or other high-impact aerobics class, for example, burns 504 calories in one hour and 13 minutes.