For you own private sundial-

Take one sunny afternoon, some chalk, a driveway, willing children and some time. Mark a spot for the feet. Trace around the shadow, wait and repeat.

Now that is has rained, it's time to start again.

I had a vague recollection of walking to the neighbours with roller skates but really had no idea how much I would love a smooth driveway until I had children, tricycles and chalk.