Heh. I wonder how many botch dice you get on that roll. 
Anyway, here's a couple submissions from me:
Hammer of Bone-Crushing Might
This spell is an unusual combination of two spells, using the guideline that 'combining' two spells adds one magnitude if the weaker effect is below sixth magnitude.
Creating the Hammer:
Creo Terram 25 (base 5, +1 touch, +1 diameter, +2 group)
Throwing the Hammer:
Rego Terram 20 (base 15, +1 touch, +0 momentary, +0 individual)
The Final Effect:
Hammer of Bonecrushing Might
Creo(Rego) Terram 30 (R: touch, D: diameter, T: group)
This spell creates a black iron ball in the caster's outstretched hand, then immediately propels it away from his palm as if fired from a catapult. Trailing behind the ball until it reaches its maximum range, a chain of the same metal appears link by link, attached to it.
Hitting with the spell requires both penetration and a successful targeting roll (with a range increment of 20 paces), and deals +15 damage on impact.
And another effect that magi would often learn to accompany that one:
Boneshattering Flail
Perdo(Rego) 20 Terram (base 5, +1 touch, +0 momentary, +1 part, +1 rego)
This spell, based on Obliteration of the Metallic Barrier, is typically cast on the chain of the Hammer of Bonecrushing Might, using target: part to actually affect the ball, which explodes in a hail of shrapnel, spreading a good ten paces in each direction and dealing +10 damage to everyone in the radius of the effect.
In my games, these two spells can be found bound in a book which also contains a tractatus on spell mastery for each spell and a tractatus on Terram. The first of the two spells was submitted to one of the House Bonisagus folios.
A possible variant of the first spell, which would be level 35 to encompass a longer duration than 'diameter', might create a grappling hook instead of an iron ball.