K'Cee loves light (flashlight, laser light, sunlight reflected off of glass) and shadows.

Grace love Qtips. You can pretend to have a Qtip and just wiggle your hand by your ear, and here comes Grace. She'll paw and cry until you give her one. She also does the paw/cry routine if your standing near the bathroom vanity (oh and she surely does know which drawer they are kept in).

Sid loves decorative flowers/vines. We have a fake pot of geraniums on the kitchen table... about every morning we wake up to see they have been removed from their pot, chewed on, etc.