We've always got a sensory bin or discovery box on the go here. The kids love them and I get a very real sense of accomplishment from making them (until the kids get hold of them and most of it ends up on the floor). Speaking of which, there is an awesome post here about how to cope with sensory bins if you are mess aversive. My experience is that the depth and quality of play that emerges from a good sensory bin or discovery box is well worth the mess. Below you'll find pictures and links to all my sensory bin posts.