I've noticed that this seems to be some sort of trick music composers have been using more and more of recently. Consider this song for example:
Nothing is odd for the first 15 seconds, then the beats come in on a different timing and stay there for the remainder of the song, whereas the, er, bell-like sounding instrument only lingers for a few more seconds before exiting stage left. Surprise! You have been "off beat" all along!
I've noticed using this especially in less classical music pieces such as dubstep.
I'm wondering if there is a more formal name or characterization for it, given that I realize I've been pretty inaccurate in my use of words.