I know most of you are still in the newborn stage, but in a few months when you're searching for new activities to entertain them you might try "washing dishes". Kids love water! My daughter (now 3 1/2) still loves being given a bucket of soapy water and all of our "dirty" plastic dishes to scrub clean.
And both kids love to water the plants outside (well, usually the dirt or brick walkways, but whatever!) with their mini watering cans.