My 4 year old son, his grandmother, and I were in the car, going through the drive-thru at McDonalds. My son always gets a chicken nugget happy meal, but I always ask him what he wants to drink, as it usually varies between a juice box or orange drink. So I look in my rearview mirror to ask him what kind of drink he'd like, to which he replies, as serious as a heart attack,
"I'll take a diet."
Both grandmother and I lost it!
Also, my son LOVES to yodle. Don't ask, I have no idea where he got it, (naturally suspect tv), but out of the blue, he'll burst into a really boisterous yodle, and it cracks me up everytime. I love it.