We write our week's memory verse on five or six balloons, and then tape them to the puppet stage. One of the teachers comes up front and has the children say the memory verse with them. Mr. Sin then comes up, and tries to convince the children to not listen to the teacher, but to listen to him and not say the memory verse. He then pops one of the balloons, and leaves thinking he has ruined it for the children.  (We put a pin on Mr. Sin's chin for him to pop the balloons with.) 
The teacher then has the children say the memory verse with one of the words now gone. Mr. Sin comes back up angry, and again tries to get the kids to listen to him, and not say the memory verse.  He asks the kids if they really believe in what the Bible says, and the children without any coercion from the teacher will answer yes. When he fails, he again pops one of the balloons and leaves thinking that they surely won't be able to say the memory verse now. This goes on for as many balloons as you have. When the last balloon is popped, Mr. Sin leaves for good, but the children have memorized the memory verse.