Over at Quiddity, Andrew Kern writes,
"How to bore a child: Try to entertain him.".
I would say the same applies to the church.
How to bore a congregation with God's word: Try to entertain them.
From my childhood I've heard many sermons, from Sunday mornings and evenings, to special speakers brought into the church for special evangelistic efforts. I've also spent most of my years attending Sunday School. What I've invariably found is that those who try to be funny throughout the sermon, or to make Sunday School "fun", end up being remembered as being entertaining, but not for the message from God's word they are trying to convey. Humor can be a tool to convey a point or put an audience at ease, but a constant stream of cleverness often just puts the focus on the speaker or teacher rather than on God.
Really, the Bible is truly fascinating enough if its message is clear and not clouded. Preached in love, intelligence, good will and good humor it will result in something real to hold onto - and a congregation engaged in real, exciting thought and action.