My little one year old girl loves to play with water bottles. Always taking them, and me worrying she is going to get the top off and choke. She doesn't think they are very much fun with out the cap, they just go flat. So today she and I made her a new toy. We took the label off the water bottle, filled with tap water and left about 1 1/2 inches of air at the top. We have this ice cream bucket of mismatch beads my son bought at a garage sale (all by himself at age 4) for a buck. Two years later it is still almost full. So my little girl and I put the beads in the bottle until the water was right up to the top. She decided it was also really fun to take hand fulls of beads and shake her hands, so we had a few hundred beads to clean up, but at least she did help pick them back up too. Anyway, when we got the bottle full, I took some super glue and glued the cap back on. Now she can play with a really pretty water bottle, and I don't have to worry she will choke.
I did have to tell her, "No, no, no, that's mine." That made the bottle even more fun.