As silly as this sounds it actually has truth. Jello or gelatin is made from animal collogen.
"In all animals-including man- collagen is an essential structural protein that forms an important part of bones, tendons, and connective tissues. It is a tough insoluble protein that is essential for keeping the many cells and tissues of the body together. Gelatin contains an exceptionally high content of two amino acids which play an important part in collagen formation, namely proline and glycine.
In fact, it takes 43 grams of dried egg whites or 35 grams of dried non fat milk or 89 grams of lean beef to equal the amount of proline in just 10 grams of hydrolyzed gelatin. Though the body can form these two amino acids on its own, it has been suggested that under certain conditions the rate of synthesis may be insufficient to provide essential body requirements and degradation can exceed synthetic processes (i.e. there is a steady loss of body collagen). The intake of hydrolyzed gelatin appears to be an alternative route to getting chondrocytes (cartilage producing cells) and osteoblasts (bone forming cells) of the body sufficient amounts of these important amino acids for making structural proteins. Although chondrocytes are critical for collagen formation, their number is limited and their ability to form this much needed protein is influenced by heredity, age, physical activity (too little or too much), injury, and availability of nutrients. "
also...
"In 1998, a small Nabisco Company-sponsored study at Indiana's Ball State University found that gelatin supplements helped to keep the joints of athletes more flexible and could even help to lessen pain. Nabisco promotes this product under the name Knox NutraJoint."
If joints are an issue I would also throw in Glucosamine Chondroitin, MSM, and Fish Oil (reduces inflammation). If you want to take a proactive stance, all of these are great supps to take year round no matter what your age. Quality Glucosamine Chondroitin at optimal dosages can get a little pricey. It is probably the most effective OTC joint supplement though. Gelatin can be obtained for very cheap prices. I packet of generic gelatin a day should do the trick.