Some types of humorous poems include doggerel and limericks. Epigrams, which are often as short as a single sentence, may also be humorous.
Doggerel is a kind of verse intended to be humorous on account of its deliberately poor composition. It is often characterized by forced rhymes or a discordant metrical pattern.
Limericks, which are often aimed at children, are characterized by their sustained and musical meter, and this is consistent in virtually all examples.
Limericks tend to be structured as narrative jokes, saving the punchline for the end. Like jokes, they lend themselves well to memorization and re-telling because of their sing-song rhythm.