Well the last thing I designed was a helm, how about an item that is a bit more serious for DnD Next?
Quick Spell Ring
Ring, rare (requires attunment)
This simple white gold ring is marked with an etching of a spellbook.
When you prepare spells, you my spend two spell slots. One of these spellslots much be higher then or equal to the other. As a free action, once per day, you may cast a spell with a level equal to the lower of the two spell slots.