My kids love to help water plants, but indoor plants, and little kids who are abit sloppy in their pouring, and light colored carpet . . . not always a good mix. I'm not sure if I read about this somewhere or just stumbled upon it, but we use ice cubes to water smaller indoor plants. I started doing it w/ my aloe vera plant (that shouldn't be watered very often in the winter anyway), if I was getting ice for something else & dropped an ice cube I'd toss it in the aloe vera plant instead just throwing it in the sink, now we use ice cubes whenever the girls want to help me water plants. And it's especially convenient for my hanging spider plant, I'm not so good at getting water into a plant above my head w/o spilling, and it's a pain to have to take it down off the hook to water it, so now I just grab a couple ice cubes & stand on one of the kids' chairs & slip them in.
And that's what works for me! To check out what works for lots of other people, pop on over to Rocks in My Dryer.