I agree that getting tight/defined abs doesn't require weights. Just diet and good ab exercises. If you need weight do
hanging leg raises.
As three norms mentioned you don't need formal weights to get a good workout. Milk jugs filled with water are great for homemade weights. An old broom handle is good for ab twists. And if you want weight, you just put the mild jugs hangin on each side.
Go to any playground and you can do pullups or
hanging leg raises. Just get creative and you can make yourself a makeshift gym.
If you don’t have weights, fill a couple of water bottles with water, and use them. Make your own weights for legs and butt by cutting a pair of old stockings and fill the legs with rice. Tie them and put them around your ankles.
You can make your own weights by filling old socks with beans or pennies, or partially filling a half-gallon milk jug with water or sand. Used equipment can be purchased at some athletic stores and can usually be found in newspaper classified ads.
1) Tennis Balls
Cut a small slit in one side of the tennis ball and fill the ball with pennies. Once the ball is full seal the slit with Super Glue, or some other reliable sealant. You now have a light dumbbell.
2) Tennis Ball Can
Remove that balls from the can, fill the can with sand and replace the lid. It's a good idea to wrap the can with athletic or electrical tape. This will prevent the lid from working itself off, and will prevent spills in case the can cracks. You can also use a Racquetball can. This gives the "next size up" dumbbell.
3) Milk Jugs & Paint Cans
Fill the empty milk jug or paint can with sand and replace the lid. You should use some type of sealant to help prevent the lid from working itself off. These are your heavy dumbbells.
4) Playground Balls
You can find these balls in the toy section of most larger stores like Wal-Mart. You can also use the type of balls used on the playgrounds for kickball. Pop the plug on the ball and let all the air out. Now fill the ball with water. This can be a little time consuming, you can either hold the ball under the faucet or submerse it in the bath tub. Make sure to use cold water, if hot water is used the ball will expande while filling, but when the water cools it will not return to its original size and you will have air pockets in the ball. Once full of water replace the plug. You now have created your own medicine ball. For a heavier medicine ball simply choose the "oversized" balls found in toy stores and toy sections of department stores.
http://exercise.about.com/od/equipme...t_exercise.htm