The cool thing about @cstross's The Laundry Files series is that it posits that magic is a branch of applied computation.
And if you understand how Turing completeness works, that means it's possible to summon Cthulhu by playing Magic the Gathering, or carefully organizing a couple million migrating crabs.
I imagine The Laundry has a reoccurring problem of their techs treating it like the "Can it run Doom?" problem and doing Bad Ideas just to prove it's possible.