Are you busy and never seem to have time to work out? No problem. Here are a few 6 pack exercises you can do in the comfort of your own home or hotel room:

1. Legs Up Crunch. This one is very simple. Lie down on your back. Now straighten out your legs towards the ceiling. At this point, stretch your arms as well towards the ceiling. Then crunch, lifting your shoulder blades off the mat. For extra intensity, try to reach your toes with each crunch that you do. Do this one 20 times. Repeat two more times.

2. Bicycles. This 6 pack abs exercise effectively works out your obliques. Lie down on your back. Clasp your hands behind your head, with elbows pointing out. Now get both stretched feet off the ground (about 6 inches) and bring in your left knee towards your chest. As you do that, try to meet your right armpit to your left knee. Then, go back to the starting position. As you stretch out the left leg, bring in the right knee towards your chest. As you do, bring your left armpit towards your right knee. When done properly, it looks like you're riding a bike. As one knee comes in, the other leg stretches out. Repeat this movement 30 times (15 each side). Then repeat the exercise for two more sets.

3. Hip Ups. Now that you've worked your upper abs and obliques it's time to work out your lower abs. When done properly this 6 pack abs exercise can be killer. Start by lying down on the ground on your back. Stretch your arms out towards your legs, palms down touching the floor. Now bring in your knees and stretch your legs up towards the ceiling. As you do, make sure the movement comes from the lower abs. Your hips should slightly come off the ground as your legs stretch upwards. Now come back down and let the hips touch the ground. Repeat 10 times, holding the contraction for 2 seconds each time. Repeat this for two more sets.

4. Plank. This is yet another highly effective, but tough 6 pack abs exercise. To do it, lie down on your stomach. Now bring your elbows in with your forearms touching the ground. At this point, go into a pushup position, with your forearms touching the ground (your palms down, also touching the floor). All your weight should be on your forearms and toes (keep the feet together). Now keep your body straight and hold this position while contracting your abs for 30 seconds. Relax and repeat. Do this for a total of 10 reps. Repeat once more.

So there you go. Now there's no excuse not to work your abs with an effective 6 pack abs exercise. Just follow this routine, no matter where you are, and you'll have worked your abs in as little as 20 minutes. Best of all, you don't need any special equipment or even a gym membership!