On My First Million, Mark Pincus laid out the whole Zynga thesis. Find a mature market that's dead and played out, that VCs won't touch, but that still has a lot of money in it.
For him that was video games. In 2007 it was a $23b industry, barely growing, not fundable. Today it's $283b and still not fundable. His line: we're living in 2007 again, consumer isn't investable, so go do consumer.