Word ladders are Lewis Carroll’s idea. You start with a word and change only one letter at a time to reach another given word. Each rung must form a new word. If the start word and the end word are opposites, this is called a word doublet.
For example, you can change LOOP to POOL, and WARM to COLD, in only 4 moves. You can get from FIND to LOSE, and LOVE to HATE, in 5 moves. It will take you something like 15 moves to get from LARGE to SMALL. A scrap of paper and a pencil or biro is all you need. Racing each other is fun.
As a variation, especially if you’re working together, make a ladder with no end word in mind – just make as many words as you can.