In grad school I took a class on creativity from Mihaly Csikszentmihalyi[1]. He described a creative idea as something that stands apart from other ideas in the same basket.

Think of a large pile of plain ol' red bricks. Now show that pile ask 100 people who know nothing about bricks the question "what can yo do with this pile of bricks?" If 99 people say "build a worker computer by ", and 1 person says "build a house", then "build a house" is the most creative answer in that sample.

Writing a SQL ad that was basically just a simple query using SELECT, FROM, WHERE. If 100 SQL writers wrote an ad, I don't think mine would have been all that creative, using the definition mentioned above. But as the only SQL-flavored ad in the personals section, it stood out as creative :)

[1] https://www.amazon.com/Creativity-Flow-Psychology-Discovery-...

I would suggest Creativity: The Psychology of Discovery and Invention by Mihaly Csikszentmihalyi [1]

I have not read the book yet but it is on my reading list. I'm currently going through "Flow: The Psychology of Optimal Experience" [2] by the same author and it is illuminating to see the author examine a simple process such as enjoying a walk and reveal the intricate interplay of our consciousness, attention and self.

[1] http://www.amazon.com/Creativity-Psychology-Discovery-Mihaly...

[2] http://www.amazon.com/Flow-Psychology-Experience-Mihaly-Csik...