I like to remind myself that accordions make people smile. It's hard to be sad when you see one, and most of the time, accordions are associated with happy moments -- aside from the rare times when I've played it at a funeral. And I like to think that even then, the bizarre instrument gives people a bit of levity at a grave time.
You know what else is always associated with fun times? Fake snoring. You know, the big noisy inhale, followed by a loud "psssssssssewwwwwww" of an exhale. I can't think of a single moment that involved fake snoring that wasn't pleasant, whether it was my dad pretending to be asleep so I could put barrettes in his hair, or me pretending to be asleep on a car-ride home so my parents would carry me inside, or just having a laugh with friends.
So if you're feeling down, try finding an accordion or do some fake snoring. It's a pretty easy April Fool's joke, I guess.