What it is: Besides a mental condition that makes us question the name? Well, hot on the heels of P90X, Insanity is yet another advanced, maximum-intensity system from the folks at Beachbody. The 60-day regimen with trainer Shaun T includes 10 DVDs, a nutrition guide and a calendar to help you track your progress and whip you into shape through max interval training (meaning you do really tough workouts with small periods of rest in between).
What it costs: $169.99
Why it's fun: Well, if you like boot-camp-style workouts, it's fun. Plus there's no equipment to mess with, and you apparently see great results if you can stick with it through the entire 60 days (assuming the box doesn't scare you away).
What it is: If you liked her 30 Day Shred (and a lot of people did), you'll look forward to "The Biggest Loser" trainer's latest routine. It features four levels of workouts set over four weeks, with a 30-day meal plan, all designed to get you in shape within a month.
What it costs: $11.99
Why it's fun: Well, the routines get harder as you go and Jillian is not exactly easy on you (you expected otherwise?), but you can control her with the pause button (Ha! Kidding.). Also, she includes modifications for beginners versus advanced students, and the quick, 24-minute routines that are easier to work into your day.
What it is: Fitness and technology at its most innovative. Developed by a Nike Pro trainer and inspired by world-class athletes' routines, this app for the iPhone and iPod Touch allows you to access more than 60 workouts and 90 multidimensional drills based on strength, cardio and core training.
What it costs: Nothing!
Why it's fun: Besides being free and pretty cool? It makes working out doable anytime, anywhere, for as long or as short as you want. Plus you can watch video demos, get trainer instruction and pick out music as you go. Genius!
What it is: A really hard-to-pronounce yet buzz-worthy workout from Pilates expert Anna Rahe that uses original, spring-loaded equipment and choreography to help you "achieve radical body transformation." Also incorporated is a body-balancing diet based on your blood and Ayurvedic types.
What it costs: $15-$35 per class
Why it's fun: Aside from sculpting your body into (you guessed it) a dancer's physique, it has helped some students relieve chronic pain issues and feel more free and childlike during class. (Now, if they could just start teaching it outside of California and New York ...)
What it is: This video game on Kinect for Xbox 360 (think Wii Fit) lets you put your body into the game and acts as your personal trainer. With workouts created by "Women's Health", it tracks your movements, gives you feedback and builds workouts based on your body type, fitness level and goals.
What it costs: $49.99 (downloads are extra)
Why it's fun: 1. It's a video game. And 2. You can download "Dance Workout: Bollywood" from XBOX Live in addition to the celeb-trainer-approved exercises that already come with the program.
There's nothing like the feeling you get after a good, adrenaline-fueled workout -- your endorphins are high, your body is tingling and you feel way better than you did before, even if it was a total pain to motivate.
But while falling in love with a fitness routine can be amazing, falling into a rut can be a drag -- especially if it starts taking a toll on your waistline. Sure, there are tons of incentives to join a new gym at the beginning of each year, but sometimes the holiday-fueled gusto behind your New Year's resolution wears off; other times, you're just over the gym and ready for a change of scenery. Most of the time, it's just that: time. There's not enough of it, and you don't enjoy your current fitness routine enough to make any. So bottom line, it's all about change.
Fortunately, getting out of said rut isn't as hard as it seems. There are a million (OK, 12) great reasons to put down the potato chips, drag your butt off the couch and start getting excited about working muscles you never knew you had.
In DVD, class or downloadable form, these popular new fitness routines take their inspiration from dancing, yoga, boxing, boot camp, even childhood activities. Some are the secrets behind the sculpted bods of celebrities such as Natalie Portman, Hilary Duff, Sofia Vergara and Kelly Ripa. All were created to kick your butt, improve your confidence level and make you a healthier, slimmer person. Trust us, you'll actually want to get up early after trying some of these. Check out what we deemed the 12 coolest ways to sweat off calories -- until the next great workout routines come along.