Lol, yeah. It's a legitimate USA holiday. But it's not a federal holiday; so no banks or courts close down because of it (like Christmas or American Thanksgiving).

It derives from German immigrants and a superstition that was based around a type of great badger or bear deity that could predict the weather. But since groundhogs are everywhere where the belief stems from in New England, they used those instead for some reason.

And if you were curious; the Groundhog (aka. Phil) saw his shadow... so according to tradition, there's going to be 6 more weeks of winter. lol

Here's the official website to the Punxsutawney Society for Groundhog Day. There you can also find the game that advertises Vaseline:

http://www.groundhog.org