Hide an object in the house and have your little one search for it. The closer they get the "hotter" they become; the farther the get to the object the "colder" they become.
Claire's comment: Robbie, this is a great game for little ones - they just love trying to find hidden objects, especially when they have someone's full attention!
You could also add some different words to shout out such as "freezing!" or "boiling!" when they are really far away or really close.
Here's a nice vid from YouTube about how to play the hot or cold game for kids:
