My niece is 5 and my nephew is 2, so they come up with some funny stuff.
My nephew is not a big talker, we call him the one word man. However, at this past Christmas, he crawled under my grandma's coffee table, waited until he thought everyone was looking at him, then started yelling, help help I tuck, I tuck! (stuck)
My niece at age 3, when asked what she wanted to drink, informed me that she wanted apple juice because it would make her heart happy.
She told me shortly after losing her first two teeth in a week (this past November) that the reason she had been so good lately was because now that she was losing her teeth, she was growing up.
I think my favorite things recently though, were when my nephew had his woody doll from toy story and the hat kept falling off. He would look up at me with this sad little face, and say "Uh-oh, Woowy"! And my niece is forever drawing pictures for us as a surprise, so she wants you to close your eyes and hold out your hands. Only she says close your eyes and hand out your hands!