NSDate.swift

import Foundation

extension NSDate {
    convenience init(year: Int, month: Int, day: Int) {
        let now = NSDate()
        let calendar = NSCalendar.currentCalendar()
        let components = calendar.components([.Year, .Month, .Day, .Hour, .Minute, .Second], fromDate: now)
        components.year = year
        components.month = month
        components.day = day
        let date = calendar.dateFromComponents(components)
        self.init(timeInterval: 0, sinceDate: date!)
    }
}

let birthday = NSDate(year: 1987, month: 6, day: 2)