If your kids are anything like mine, then they LOVE baths! Like, could spend hours in the bath tub or shower if I let them. There was one winter that Max took two baths/showers a day to keep entertained! I was pregnant and horribly sick with Harrison plus it was sooo cold and snowy out, we hardly left the house. That's when I discovered his love for water, bath crayons, and experimenting with turning the water different colors. Here are a few of my kid's favorite bath time toys and activities:
Crayola Jumbo Bath Dropz (Crayola Jumbo Bath Dropz Scented, 3-color Bath Fizzie): The kids just tried this the other day and it was very cool! Just as it sounds, it's a huge bath fizz ball, that changes into 3 different colors as it dissolves. Max has very sensitive skin, but I've never had an issue using any kind of fizz colors and water coloring items. Harrison of course touched it as it was changing colors and it did stain his hand. Even after washing the color was faintly there, but it had completely faded away by morning.
Sesame Street Fizzy Tub Colors (Sesame Street Fizzy Tub Colors 50 Count): We've used these on and off for years and they are fantastic.
The fizzy's dissolve quickly with bright colors. No issues with staining skin, tub, or floor (yes, water ALWAYS winds up on the floor with my kids!).
Bath "paint": I have bought the Crayola bath paint (Crayola Bathtub Fingerpaint Soap by Play Visions)
before and it was great, but my kids go through it very quickly so the cost adds up. That's when I started making my own. Put baby soap (we use Johnson's hypoallergenic Body Wash) in muffin tins and mix in food coloring. Sit back and let the kids paint the tub/shower walls! You can always put a cloth in their hands and tell them to scrub the "paint" off when they're done. Keeps them busy longer and I'm getting the shower cleaned mid-week. Double bonus.
Ice cubes w/ food coloring: All of those products that change the bath water different colors can get expensive if you're kids are like mine and go through those things fast. That's when I resort to making ice cubes and dying them with food coloring. Once they're frozen, pop those babies out, and put them in the warm bath. My kids get into watching the cubes melt and change the water colors. This won't (or at least it hasn't for us) stain skin, towels, or the tub, but just a warning, these only tint the water. It won't be the vibrant colors you get with the fizzy tub colors, but still fun and cheap.
Bath Stickers and Letters (Rub a Dub Stickers for the Tub - Colors May Vary and Little Tikes Bath Letters and Numbers: I found the bath "stickers" on Amazon months ago and bought a set at Target for the kids. Only $4.99 for a package, they make different varieties (I went with zoo animals, but ALEX tub brand has a transportation set that looks cool), and once they're wet, they actually stick really well to the sides of the tub. I buy the Munchkin brand of sets of letters and numbers from Target. The only bad thing about the foam letters and bath stickers: they seem to be one of Elizabeth's favorite teething toy, so ours got chewed up fairly quickly. Would be great for kids old enough to know not to bite.
Bath Crayons (Munchkin 5 Piece Bath Crayons Set): My kids LOVE these, I do not, so I don't buy them often. We have tried the Crayola and ALEX brand bath crayons. Both scrub off of the tub surfaces (and the floors and walls, fyi) easily and they do provide lots of fun for the kids. However, my kids go through these fast and they're on the expensive side when I would need to replace them every week or more. So, these are a "special item" in our house. I've seen several things on Pinterest for make your own bath crayons, I just have yet to try it out.
Bath Squirters (Fisher-Price Thomas Bath Squirters): Of course, any toy that squirts water is a favorite of any child's. Just be sure to check for mold regularly. I've thrown many out and expect too if you have any. I continually check Target's dollar section and other cheap place for squirters, so I can replace the moldy ones without the kids noticing.
Hopefully these can add a bit of fun to your child's bath routine!