Pick a topic (like animals, birds, fish, insects, trees, plants, names, relative names, Bible characters) and go through the alphabet one letter at a time. Each person must list something different, yet starting with the current letter, that belongs to the topic.
Take turns from youngest to oldest if kids are playing, otherwise rotate who starts, as the final person each round has the hardest job to think of item for that letter which has no yet been said.
Once you've succeeded through the whole alphabet, try a new topic.