I found the Leapfrog Alphabet Pal a great learning toy that spans many ages. It was purchased for my son when he was less than a year old. At first, it amused him by playing the songs and letters as he randomly pressed the feet of the caterpillar. As he grew older, he used it to sing his alphabet and identify his letters. Now, even though it's supposed to have been put away for my daughter to use when she gets older, I recently found it in my 4-year old son's room as he continues to play with it.

Although it has a string for pulling it behind you, I never found that my son used this function....