Hickory dickory dock (sounds like a clock ticking)
The mouse ran up the clock (winding up the weight)
The clock struck one (an hour or so later)
The mouse ran down (weight is at the bottom)
Hickory dickory dock (time to reset the clock)
On researching this rhyme further I discovered that in different countries it has different meanings. In the USA it refers to plants and is a nonsense poem and also used to teach children to tell the time. In the UK it refers to the numbers eight, nine and ten in the Borrowdale dialect. The earliest recording of the words is from 1744.