The band Nirvana does not practice nirvana. Om practices Nirvana.
Nirvana, simply put, is letting go. Only by letting go of everything can you see everything for what it is. It's nearly impossible to do that. Everything bogs us down. Everything sticks in our throats and makes us anxious. It doesn't matter what it is. Late on child support? Not enough courage to talk to a cute girl who might reject you? Afraid your children aren't going to amount to anything? Worried about global warming? Freaking out about your imminent death? You are not letting go.
Letting go is not the state of non-existence. Quite the contrary, the principle is that only by letting go can you see things for what they really are. The question is: can you let go?