This was in the Boston Globe Magazine and I emailed it to a friend so it qualifies as an email joke. You have to know the Boston accent to get the humor.

Going to the potty

I had to run to the restroom just before the conclusion of a recent show at the Wang theater. Near the lobby, an usher with a clipboard stopped me and asked, "Are you going to the potty?" I said yes. She then asked for my last name and looked for it on her list. Thinking that slightly odd, I offered her a look at my ticket stub. She informed me that my name was not on the list and asked if I had a special sticker. Exasperated, I finally asked, "All this to go to the restroom?" Looking surprised, she replied, "I thought you said you were going to the afta-potty."
Les Taylor / Marshfield