Enter Katz's Delicatessen, at 205 East Houston Street and, just as you begin to look around and soak in all the amazing smells, some guy hands you a ticket. If you look like a first-timer, he issues the warning, Don't lose that, you'll need it to get out. It's like the Metro in DC. Except this ticket is imprinted with a strange, iconic grid of numbers clearly from an earlier time (Katz's opened in 1888).
Here's how it worked: Start in the bottom right. The "50" means 50¢, and the small "4" next to it indicates that tax on 50¢ was an additional 4¢. If you bought a hot dog, and it cost 50¢, they punched a hole in that block of the grid. If you then purchased a corned beef sandwich from a different deli man for $1.60, then he would punch a hole in grid block "210" -- meaning, your new total check was $2.10 plus 17¢ tax.
That's it. Now they write on the reverse side with black marker. The grid is nostalgia. It's also a tee-shirt. "1500" -- tax included.
Map Katz's (call ahead for days/hours).