Simple Code 3 - PigPen 2

Ready for your first puzzle?
 
These Simple Code puzzles (Set 2) start with a funny joke, and the student finds the punchline by swapping out a PigPen symbol for a letter.
 
That's all there is to it!
 
No math or other primary school skills needed. 
 
Each puzzle has an explanation how to decipher PigPen code.
 
Ready to solve? Let's get cracking!