We recently checked out a book from the library about opposites. These really cute little ducks do all kinds of opposite things...close/far; short/tall; and Amelia's favorite - heavy/light. She can't get past this page without giggling outloud, which makes me giggle, and before you know it, we're both laughing at each other.
What makes her laugh is that one duck is carrying the other duck in his arms (heavy), and on the next page the lazy duck being carried puts a feather on his nose and tries to look at it. For some reason, this feather tickles her no end. She has been trying to put a feather on her nose ever since. We have feather pillows in the house, so I plumped them up and pulled out a little feather for her to play with.
She immediately put it on her nose and then tried to look at it, laughed, and blew it off into the air on accident. The next hour was the easiest hour I've had in a long time. I never knew a feather could be so entertaining. She even convinced me to try it on my nose a few times! Days later, she is still playing with that feather and getting the giggles.