How about every single church out there with an insurance against "Acts of God?"

One full hour of constant music can be tiring not only for the performer but more so for the audience. I think good, tasteful jokes give breathing room between songs.

Of course, jokes don't translate very well into another language/culture. For instance, how can you translate into another language, "Why can't a bicycle stand alone on its own?" "It is two(too) tired." However, when dealing with an audience of the same language, good humor can be very effective as I've seen other musicians.