Scala would be more fun if it had one of these...

Schrödinger.scala

final case class Schrödinger[+A, +B](a: A, b: B) extends Either[A, B] {
  private var isleft = true
  private var isright = true
  lazy val actual : Either[A, B] = {
    if (new Random().nextBoolean()) {
      isright = false
      Left(a)
    } else {
      isleft = false
      Right(b)
    }
  }
  def isLeft = isleft
  def isRight = isright
  def left = Either.LeftProjection(actual)
  def right = Either.RightProjection(actual)
}

needs moar laziness:

class Schrödinger[+A, +B](private a: => A, private b: => B)

and you can make isLeft/isRight lazy vals too:

lazy val isLeft = actual.isLeft
lazy val isRight = actual.isRight