and here is an idea which, although simple, is guaranteed to put a smile on your child's face. Simply plop a few glow sticks into the bathtub with your kiddos, turn off the lights and watch the magic begin. Curve a glow stick and hold it by your mouth to imitate a smile or a frown...grow horns from your head....drip a small puddle onto the side of your tub and place a glow stick in it to see the way the water turns color...or simply wave a couple of glow sticks really fast and watch how the color blurs in the darkness. The options are endless and kids will really have fun being creative.
A word of warning: Do not take an overtired two year old into the tub on glow stick night. He/she will not want to get out, will insist on sleeping in the tub with his/her glow sticks, and upon finding out sleeping in the tub is not an option will splash enough water around the bathroom that you will think about having a drain installed in the floor. The upside is that your bathroom floor will get a thorough mopping!