Maybe they’re going to be slingshotting some birds from the observation deck?

Tomorrow is the official launch of the highly anticipated “Angry Birds Space,” the next installment in the blockbuster action-puzzle game from Rovio. And it looks like Seattle’s Space Needle is going to be playing a central role.

The official Angry Birds account on Twitter posted the image above today, teasing a Space Needle launch event on Thursday, and saying only that “something big is happening” in Seattle.

It doesn’t look like any similar events are planned for other cities.

“If you’re near the Space Needle, head down!” they replied, vaguely, to one person asking for details.

The Wal-Mart and T-Mobile billboards make sense, given the Angry Birds promotion announced by the retailer and wireless company today. But presumably there’s more to it than that.

We’ve put out a few calls and messages seeking details on the event, but we’re hearing that Angry Birds maker Rovio is being purposefully, well, cagey about its plans. We’ll update this post if we turn up anything concrete in advance.

In the meantime, given T-Mobile’s involvement, we’re crossing our fingers for something like this …