Well, okay; it's not his birthday quite yet. That's coming up (the centenary, no less) on February 3rd. But headlining it now will give you time to get your party together.
And to properly prepare for it, you'll have to read through Don Feder's brief but delightful tribute to America's favorite artist. Check it out right here.
And for more info, you might take a look at the online site of the Norman Rockwell Museum, the "official site" of the artist, and the Rockwell Gallery Collection.