Olivia has learned to clap. It doesn't matter what she's doing, if you say, "Yaaaay!" she will stop what she's doing and clap.
She'll even do it when you say, "NO!!!" like when I found her digging in the nursery trash can this morning. She sat down, smiled sweetly, and clapped. This replaces the hysterical laughter she used to exhibit when I would say, "NO!!!"