Ok, maybe it's late, but I thought of a game that might be fun to play here... Let's call it the Adsense niche word association game. I'll start with a word, and look up the estimated CPC with the adwords tool thingy at https://adwords.google.com/select/KeywordTool You think of a word associated with that word, look it up and post the estimated CPC. And on and on. The purpose? To provide inspiration and get an idea of how big the keyword market is. If this sounds kooky and I need to go to bed, I understand. On that note... I'll start the game with the first word.. That word is... insomnia for $3.52 a click
Just to make sure everyone knows what I mean, the word "insomnia" might make the next player think of "pillow" and lo and behold "memory foam pillows" shows $3.79 a click