I'm wondering if it was some sort of orbital projectile weapons system, being tested under cover of the asteroid's passage. But first I want to see more details of the argument that they couldn't have been part of the same cloud of rocks - e.g. could the Chelyabinsk meteor have been an outlier which fell into Earth's gravity well at a distance and arrived from a different direction.
edit: Maybe a more plausible version of the idea that the Chelyabinsk meteor was artificial, is that it was a secret satellite which was being disposed of ("de-orbited", re-directed on a collision course with Earth). Chelyabinsk area seems to be full of secret installations, so if there's debris, at least the men in black don't have far to travel.
edit #2: The general options seem to be: artificial; natural and related to the asteroid; natural and unrelated to the asteroid. Better probability estimates for each option should be forthcoming.
This thing came in at significantly greater than orbital velocity, faster than it can fall from any earth-bound orbit, and in the reverse direction from pretty much everything launched from Earth's surface (in all the wide-view videos you can see it approaching from the direction of the rising sun, in the East, and comparison of the shape of the trail with http://www.youtube.com/watch?feature=player_embedded&v=VdoKEFsemvw confirms this). It also looks JUST like any number of other meteors that have hit, and discharged as much energy as a 300 kiloton* ...
If it's worth saying, but not worth its own post, even in Discussion, it goes here.