17 Apart and thought it would be fun to try with the boys. It couldn't be much simpler: just take your grocery store celery, and chop off the bottom (root) end. Put it in a little bit of water, not too much, and you'll see some new celery growing up from the middle in a few days. When the little roots appear, stick it in some soil in a pot, and see what happens! Don't forget to check the water level and change out the water every few days.
Sick update: things are looking up, and I still haven't had the worst part of it. (My fingers are crossed that I won't get it.) I'm still not feeling quite right, though. Hrm. Thomas is fully recovered, P is almost there, and Adam is much, much better today. Things are looking up!