Jolly jumpers are great - but like all things for baby, should be used under supervision. I used one for my son Nathan, especially around witching hour, when nothing else would do, and we would put some music on, and he would jump and jump and squeal...lol. We have just started using it with Aston, and he loves it too. I usually sit on the floor with him while he jumps and entertains us all.

Like everyone else has said, they are great, just don't over use them. Have fun...