In about an hour, the Celtics and Heat will tip off Game 5 of the NBA's Eastern Conference semifinals.


They might also be tipping off the last game of the Big Three Era.


If the Celtics lose tonight, it's not the end of their championship window.


But it's darn close to shut.

Yes, the superstars -- Kevin Garnett, Paul Pierce, Ray Allen and Rajon Rondo -- are likely to be back next year. But they're going to be a year older, a year slower and a year more injury-prone. There's still not going to be a competent big man, and the draft this year doesn't look likely to provide a lot of refreshment.

Meanwhile, you have to assume the Bulls will improve, the Heat will gel and the young teams out west -- especially Memphis and Oklahoma City -- will start to stake their claim.

Garnett, Pierce and Allen provided immediate results after Danny Ainge brought them together. The latest banner in the rafters still looks sweet.

But it's almost over.

If they do go out, take solace in this: They'll do it with a lot more class than the Lakers.