I first came across the phrase "Happy Memorial Day" here.
You may want to use a different search engine. Doing a search for "happy Memorial Day", I got these results:
Google - 1,140,000 hits
Yahoo - 696,000 hits
MSN - 119,230 hits
Smiley faces, "humorous" screen-savers, car sale ads, furniture sales and too many barbecue recipes to count. Yep, that's what Memorial Day is all about.