Description (in English)
This Javascript program generates either haiku or tanka, as you prefer. The poems normally adhere strictly to the syllabic contraints of those forms, though occasionally the program will determine that its creativity cannot be so fettered, and it will produce a poem that breaks the rules. If you're presented with a 27 syllable haiku, count yourself lucky - it doesn't happen often.
(Source: Author's description on the project site)