I was really pleased to get a poem in volume II of Beat the Dust's Literary Experiment edition:
"Inspired by the idea that no piece of writing is ever truly finished, we asked writers to take what they consider to be an interesting last line of any published novel, short story, poem or song, and use it as the first line of a new piece of flash fiction or poem"
Mine is based on the last line of Charles Simic's "Popular Mechanics" and can be found here. (Volume I is still online and is well worth a read too).
Each entry also includes the writer's top 5 song intro/outros.