we used an alarm clock . set it for one hour , then worked or played until the alarm went off . then someone would use the clock REGULAR KIND NOT DIDGI ans show how it workes with the long hand as one minute and the short one the hour ....
we would later on set the clock and say in one hour we are going to have a really yummy snack . you have one hour to think what you want ... this also encouraged the littles to work together because if the couldn't decide which of the choices we set the clock again ...
didn't take too long for them to understand if we decide first we get the treat faster