This is a silly and untested idea.
But what if player's could build up to some grand finale, some kind of über powerful finishing move, but daisy chaining their spells? Maybe there's some kind of power meter, a gauge, that builds up a little bit, for every successful chain?
And how do you daisy chain spells?
Well I'm thinking, one way to do it would be to cast a spell that starts with the letter that the last cast spell ended with.
For instance: FIREBALL => LIGHT => TELEKINESIS
Each chain builds up that gauge a bit - or maybe each chain adds that spell to some bucket, that releases them all at once, when the proper word is pronounced, or decided upon, or when the chain is broken. Or record each spell level, and treat the sum as a bonus to the last spell cast that breaks the chain.
And to end this post, here's a picture of two wizards arguing: