To play Hide and Seek Treasure, first I would spread out a bunch of cardboard letters we have all over the livingroom floor. The "treasure" (a quarter) was at first always hidden underneath the "X", because everyone knows that's where you find treasures! Underneath an X! It is preschooler logic.
After a while I became a silly pirate, however, and would hide the treasure underneath another letter, so Zeke would have to find the H or the R or what-have-you to find the treasure.
This game could also be easily played with an older child, hiding the treasure underneath an object that starts with P, for instance.