Here at the Parrish household we play a game called "Ya-ya". Someone hides, and someone else has to find them. Sounds just like Hide-and-Seek, you say? True, but our version has hints in the form of the hider calling out "ya-ya!" in response to the seeker's "ya-ya" inquiry. So basically, it's hide-and-seek-meets-Marco-Polo, but with "ya-ya" as the phrase of choice. Isaac randomly started saying it years ago, I think when he was two, and it just kind of stuck.
Elinor has really gotten into the Ya-ya game and as you can see, she's quite good at it.