Groundhogs
I'm not sure where I stand on this ritual. On the one hand, I admire traditions that go back 130-140 years, even though you could go to Europe and find out every town there has an esoteric and more bizarre tradition that goes back 3+ times longer. On the other hand they don't do enough with it. It should really be more of a national holiday, complete with a day off and booze.
I think groundhogs are also too shy. I want a National Squirrel Day.