I'd like to play a wizard who specialised in the creation of magical items and potions, can do a bit of thaumaturgy but sucks at evocations completely, so his magic always needs time to be prepaired.
This means that for every spell he wants to cast he needs a carefully prepared gizmo, that contains the spell he wishes to cast. I can see the first one allready: a key that you turn in midair so it opens a door to the nevernever.
Of course most such items need to be recharched after they are used, and in the wrong hands they might even be dangerous, but thats where the fun is, I guess.