[wmwragg]

I think it's generally thought of as "lateral thinking", Edward de Bono has written a few books about it you might find interesting.

[coldtea]

And some more commonplace words like "creativity" (as in "creative solution") etc. would apply.

[bzuker]

any particular one you'd recommend?

[wmwragg]

I think the classic is "Lateral Thinking: A Textbook of Creativity"