Heard at a concrete wall...

Me: "Augh. Concrete is just spilling out of this hole. I've got to plug it with something."

M: "Here you go." (Cobbles together Rube Goldberg contraption of blocks and boards) "What could go wrong?"

Me: "GYAAH!" (Contraption collapses, and Uncle Joel is inundated with wet concrete)

M: "...Except for that..."