Definitely not the first time similar sounding call signs have resulted in pilots executing someone else's clearance. There isn't a surefire solution to every problem, but this one requires more attention to detect than many other problems do. In my experience, ATC is usually really on the ball about issuing warnings for similar sounding call signs on the frequency, but nobody can be expected to recognize it every time. Perhaps it IS time to require all call signs to be spoken alphanumerically one character at a time. That would take some time for pilots and controllers to get used to. Seems worth talking about at least...