It may be harder to smile, muscle-wise, than it is to frown, but smiling (even fake-smiling!) can help you to find things funnier and make you happier. Trace turns his frown upside down to recount some studies that have reached this sunny conclusion.
Doctors report the case of a young girl with incurable laughter, which turned out to be from a brain tumor.
Ever hear a joke that isn't funny, but you laugh anyway so the joke teller doesn't feel bad? New research says quit it! Laci discusses how most people can tell when a laugh is fake!
Laughing is weird if you think about it -- a physical response to something we find funny, or even uncomfortable. Guest host Annie Gaus explains why we do it.
Ever try to tickle yourself? It doesn't work! Anthony explains how tickling works and why it's something you can't do alone.