知り合いが誕生日だったので書いてみたら意外とめんどくさかった。
日付処理だからしょうがないか〜と思いつつすごく簡単な方法があったりして。。。

let name = "俺様"

let birthdayComponents = NSDateComponents()
birthdayComponents.year = 1982
birthdayComponents.month = 1
birthdayComponents.day = 18

if let calendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian) {
    if let birthday = calendar.dateFromComponents(birthdayComponents) {
        let now = NSDate()
        let elapsed = calendar.components(([.Year, .Month, .Day]), fromDate: birthday, toDate: now, options: [])

        let year = elapsed.year
        let month = elapsed.month
        let day = elapsed.day

        switch (month, day) {
        case (0, 0):
            print("A Happy \(year)th birthday to \(name)🎉")
        default:
            print("A very mery unbirthday to you!")
        }
    }
}