Download it now from the BlackBerry App World, $4

What It Does: This BlackBerry app lets you take it back to the days when dudes put new girl's numbers into a little black book that was safe from all prying eyes. With this app, you can securely store away any and all contact info that may disrupt your happy home, by storing it in this password-protected app. Even better, you can assign a custom name to the contact for when they call or text your phone. And if your girl does go snooping through your phone, she won't find an icon—you need to tap in a special code to access BlackBook.