Actually, in the space station. A Japanese astronaut (who knew?) has checked it out.

How about in actual space? A friend has crunched the numbers and come back with the answer:

A more interesting question is what would happen were the boomerang to be tossed outside the station where the atmospheric density is roughly .000000000001 kg per cubic meter, small but not entirely trivial. Even this thin atmosphere produces enough drag to require NASA to periodically boost the station’s orbit.
Boomerang dynamics tells us that the radius of its trajectory is inversely proportional to the atmospheric density. Consequently, the boomerang in space would describe a somewhat larger circle than it would on earth — according to my estimate one with a radius of roughly 10,000,000,000 miles. And the wait for it to return might even strain the patience the Japanese astronaut Takao Doi.

I dunno, he could practice Zen while waiting. And from the look of him, he should lay off the teriyaki for a while, anyway.