code:

// my typeclass
trait Buttlike[A] {
	def touchIt(a: A): String
}

//wrapper to smuggle the type in, thanks type erasure
case class Ev[TC[_], A](a: A)(implicit val ev: TC[A])

class BigButt

class TinyButt

//implementing the typeclasses for the butts
implicit object BigButtIsButtlike extends Buttlike[BigButt] {
	def touchIt(a: BigButt) = "fart"
}

implicit object TinyButtIsButtlike extends Buttlike[TinyButt] {
	def touchIt(b: TinyButt) = "poo poo"
}

//my list!
val l = List(Ev(new BigButt), Ev(new TinyButt))

//gonna touch those butts
l.map(_ match { case e @ Ev(a) => e.ev.touchIt(a)}) //List("fart", "poo poo")