Some of the churches' changeable signs in my area (Bergen County, New Jersey) can be very amusing, and sometimes almost witty. They're usually funny in the way one sometimes laughs at the patheticness of things that fail at being genuinely funny, though.
A few excellent church signs seen in my area:

(around mothers' day)
"Wise moms seek Jesus"
My friend's brother suggested that it should be "Choosy moms choose Jesus"

"A midlife crisis is better than a life Christless"

Just days ago, for Thanksgiving 2000, a church had "Count your blessings"
This week, joking about the 2000 presidential election, they had "Recount your blessings"

One church has a double-sided sign, with one phrase that can be seen when driving by in one direction, and a different but related phrase that can be seen from the other direction.

One side:
"Truth stands the test of time; lies soon crumble and fall"
and the other side:
"The Bible prevents truth decay"

See also:
church message sign