My big experiment with my first born was trying to teach her to count starting with 0 instead of 1. I attempted it for a few months, but ultimately stopped because everyone else around her was counting the typical way and it seemed like it might be confusing to her.. I admit it was a bit embarrassing for me when doing so in the presence of non-geeks.
I'll also go ahead and share a funny anecdote and hope it doesn't come back to haunt her in a decade.. :) We noticed a common side effect of her getting the hiccups whenever we changed her diaper. One day I jokingly said that the first time she ever came home from a date with the hiccups, her boyfriend had better start running.