Despite all the hints and reports that the band would turn up to announce details of their new record and tour, none of the four were present.

So what happened? According to Neil Portnow, chairman of The Recording
Academy, who run the Grammys, waffled:  “In the world of creativity, everything is fluid. In the process of discussions that we had been having with an expectation that perhaps we would be at a point tonight where the artist involved and we, moving forward, would be ready to announce [a reunion], they weren’t quite at that point. So it’s live television, we go on to the next act. It’s rock and roll and so on. That being said, we were genuine about the intention and we are genuine about the discussion.”

It now appears that Van Halen will make their big announcement in January, but I wouldn't hold your breath.

To their credit, the Van Halen News Desk (which is not directly associated with the band) was skeptical about the projected Grammys appearance from the start.  Below the headline "Duped By The Grammys?," the website issued the following update while speculation mounted yesterday:

"Rampant rumors have Van Halen making an appearance at the Grammy Nominations tonight to announce their forthcoming album and tour. It was the Grammy’s themselves who started the rumor. Yet some of our sources have been telling us that they can’t confirm the rumoured appearance, and others have flat out told us that it was never anything but a rumour in the first place, started by the Grammys. Whatever the case, other than the original rumor, we haven’t heard anything that would lead us to believe that the band is involved in the show tonight. Put it this way…if the band does actually make an appearance they are much better at keeping secrets than we’ve ever imagined!"

In other Grammy news, The nominees in the Best Hard Rock/Metal
Performance category are:

Dream Theater "On The Backs Of Angels"
Foo Fighters "White Limo"
Mastodon "Curl Of The Burl"
Megadeth "Public Enemy No. 1"