The CIA and China would notice and wouldn't like it

Both the CIA and China (and Russia) would have the greatest interest in keeping it secret if any such thing happened.

Admitting that any such thing had happened would cause widespread panic (we're talking about a panic of biblical scale -- the end of the world, we're all going to die -- that kind of thing), which is just the thing governments don't like happening. But worse... both China and Russia would have to admit that they couldn't prevent it. That's something they'd never want to admit.
And, yet worse than the previous, China and former USSR would find themselves in a position where they would have to do something, if anyone was to ever take them seriously again afterwards. Such thing (accidential or not) is a more or less compelling reason for war, and they surely wouldn't want to go to war against a communist brother state. Therefore, given such a hypothetical case, they would definitively keep it secret, and you would definitively never find out.

The Chernobyl incident was only revealed after some guy in Sweden wondered where all that radioactivity came from all of a sudden. If it had been for Russia, you would still not know today.

There is no sense in doing "tests" with live nuclear ballistic missiles.

There is no sense in most of what governments do, for example, developing weapons of mass destruction in the first place, or making the place where you live uninhabitable for humans, or taking up loans to pay interests on loans they use to pay interests. That alone doesn't mean they're not doing it anyway.

looked exactly like you'd expect

I totally agree. It looked exactly like I'd imagine a meteor coming down, too. However, that doesn't mean much. The meteor in the Armageddon movie looked pretty good to me, too. Tie fighters in Star Wars make sounds (in vacuum) just like I'd expect them, and the airplane crash sites in September 2001 looked pretty authentic on TV as well.

The problem is, all I've seen is stuff on TV and on youtube (and presumably the same is true for you), and neither source is reliable in any way. Nor is anything that "some super sapient expert" tells on TV or on the internet.

All you really know so far (and all they know) is that there exist some movies of "something" from an unknown source, with unknown editing, and unknown censorship. Some big smoke/vapor trail, and some glowing tail with a big flash in the lower third of the sky. Fine, youtube is full with all kinds of fake videos. Some seismologists might in addition have picked up some recordings that tell them there was indeed a big boom, ok, fine... but again, that boom could have been anything.

Unless you can lay hands on a big piece of molten metal with an "alien" composition that doesn't normally occur in Russia (or on Earth) in that form, that's about it, and for all it's worth, it could have been anything. Including a comet, a sattelite, a missle, or a smoke show for propaganda.

Seriously, a conspiracy ? Did you even watched the movies ? There's not a single missile on earth that can outshine the sun. It just does not happen. And missiles don't leave a trail of fire behind them. The fact you believe it can even be a possibility is ludicrous. And then you say the movies would be part of the conspiracy ? Laughable. The movies were uploaded from many different sources minutes to a few hours after the event, so Russians had to prepare them beforehand. Yeah right.

I thought that was gamedev here and not the flat earth society?

The fact you believe it can even be a possibility is ludicrous. [...] And then you say the movies would be part of the conspiracy ? Laughable.

Well, that is somewhat of a distorted way of putting it, but what's really scary is that you're almost fanatic about not letting the slightest possibility it might be something different than what it looks like at first sight.

What I've said is that all you have is "some videos" on youtube. They may be fake (or edited, or whatever), or they may be "genuine" insofar as they're something people really saw on the sky and recorded. However, "something" genuinely recorded may not be the same "something" that you or someone else thinks.

Although it looks like a meteor and probably is one, that "genuine something" may still be something completely different, and you have no base to prove it, other than "but it looks like...".

About 2030 years ago, one particular government had all the first borns killed when they saw a falling star. This should be enough reason to not blindly follow the first convenient explanation and dismiss everything else without even a thought. Only because someone says it is an omen, that needs not be. Only because someone says it's a meteor, that needs not be either.

Mr. Zhirinovsky seems to be convinced that the phenomenon was an US nuclear missle because Mr. Kerry was pissed off by something. Or so he said in his speech. Whatever. Now don't concentrate on how disturbed this is or whether might be true. Just consider its immense propaganda value.

And with that propaganda value in mind, you should at least deem it not impossible that an ultra-hardline nutter who likely has a way of getting hold of a nuclear missle (if you have some spare money, you got a bomb) detonates a missle in a sparsely inhabited area. It's not like Rome hasn't burned before. Nero did it, Hitler did it, and Bush did it -- why is it impossible and entirely laughable to consider that Zhirinovsky might. I'm not saying that he did, but it is a possibility.

Yesterday, it was said that the major part of the remains after the explosion fell into lake Cherbarkul (how convenient), and today some alleged tiny pieces have been found near the lake. Apparently someone found (or made) a 6 meter hole in the ice, too. Nice facts, so there's proof it was a meteor falling into the lake.

This reminds one of Nostradamus' prophecy. Something about a burning star falling from the sky and the Mediterranean Sea evaporating in 1999, remember? Oh wait, he's a couple of years late, and it's not quite the Mediterranean either. But hey, did someone say "evaporate"?

Vilem Otte calculated a kinetic energy of 1602TJ a few posts above. Let's assume that is the correct number, and assume that only 1% of this was left in the big piece falling into the lake afterwards. In the car video, what came after the boom still looked "quite big", so that's probably a conservative assumption.

This meager 1% is still the equivalent of heating 4 million cubic meters of water by 1°C, or alternatively, making 41,000 cubic meters of 4°C cold Lake Cherbarkul evaporate (that's approximately one third of the lake!). I didn't see a huge mass of steam rise from the ground in the videos, did you? I didn't read about hundreds of people getting burns in hot steam, nor about a flood wave destroying houses near the lake, did you?

Surely the meteor must have stopped moving by now. Where did the energy go?