[vunderba]

Good job. Very similar to the NPR puzzle show which provides three full words and you have to find the common one:

Cow, Flower, Hop: The answer is "bell" (cowbell, bellflower, bellhop)

You can ratchet up the difficulty by allowing homophones or proper nouns, for example: Tall, Spin, Fox...

My brother and I use to make them up and play each other on long car rides during summer vacations.