Flying monkey's planet was a planet in the Pegasus galaxy which contained an orbital Spacegate and was inhabited by "flying monkeys". Like the Wraith homeworld the planet boasted a ring system (which is unusual for a terrestrial planet).
In 2008, Atlantis 1 surveyed the planet as a possible new Alpha Site. Rather than the flying monkeys, the team did agree that it was a suitable planet, with a good climate, with abundant food and water. Elizabeth Weir's conscioussness was floating around subspace on that planet, when she found Sheppard's team leaving the planet. (SGA: "Ghost in the Machine")