Don't be the person who gets what they think is the Chinese symbol for "Love," but actually means, "I'm an idiot" - try before you ink up with the Tattoo Shop iPhone App ($2)! Upload a photo (of you, your best friend, your puppy) and temp it up with everything from pinup girls to animals to text in multiple fonts & colors. When you decide you don't like having an "I HEART PUPPIES" tramp stamp, there's no painful laser sessions: just scroll & click it away!
Bonus: Can be used to send panic-inducing photos to parents - "Hi, Mom! Having SO MUCH FUN in the Castro District!"