Don't let those winter doldrums get you down. Add some variety and spread the love to your workout routine with these at-home exercises you can do with a partner.

1. Push a wheelbarrow. Remember those wheelbarrow races you did in elementary school? It's a heck of a lot more difficult when you're an adult. It's also a great upper-body workout. To do it, the first person gets in a push-up position while the second person holds the first person's legs. Then, the first person "walks" across the floor using his or her hands. Try to go the entire length of your room and switch off.

For a new twist on this old game, the first person sits on a towel on the floor. (This will only work on tile, hardwood, or otherwise non-carpeted floors.) The second person then runs backwards, dragging the first person by his or her legs while he or she slides across the floor on the towel. It's a great cardio workout for the second person, and (depending on how far you lean back) a great ab workout for the first person.

2. Make abs a game. In this fun exercise, an ab workout becomes a game. The first person lies on his or her back on the floor, while the second person stands right over the first person's head. The first person holds on to the second person's ankles (for support), and raises his or her legs in the air, feet together.

Then, it becomes a game. The second person pushes the first person's raised legs toward the floor, while the first person does everything in his or her power to keep his or her feet from touching the ground. Switch positions after about 2 minutes, so the pusher becomes the pushee.

3. Play catch. If you have a medicine ball, this is a great way to use it. Otherwise, any basketball, soccer ball, or volleyball will work. Take a simple game of catch and turn it into a lower-body workout by lunging before every throw to your partner. When your partner catches the ball, he or she lunges and throws the ball back. To start, try for 20 tosses and lunges per person (10 on each leg). The slower you lunge, the harder it is, and be sure to alternate legs with each toss.

4. Twist and shout. Use the same medicine ball or sports ball you used in the previous exercise, and stand back-to-back with your partner. The first person holds the ball at waist height, and passes it to his or her right. The second person then turns to his or her left to take the ball, brings it around the front, and passes it back to the first person on the right. Essentially, you'll be making a big circle with the ball. Be sure to concentrate on your core muscles as you pass the ball, and remember to switch directions after 1 minute.

5. Modify leapfrog. Update this recess game and turn it into a core workout. The first person gets in a push-up position and holds it while the second person jumps over the first person. Once the second person has cleared the first person, he or she gets in a push-up position so the first person can then leap over the second person. Continue alternating until you run out of room, or go for 3 minutes.

6. Stretch it out. After any workout, it's important to stretch. One great partner stretch is for your legs. The first person lies on the floor and raises one leg. Standing up, the second person takes the first person's leg, places one hand on the first person's knee (to ensure that the leg remains straight), and gently pushes the first person's straight leg toward his or her torso. Hold this position for about 15 seconds, and then bend the first person's knee and lightly press the leg toward the body for a stretch of the glutes, hamstrings, and quads.