There are actually lots of very exciting GP applications! One of my favorites is "Fixing 55 out of 105 bugs for $8 each", in which GP is used to automatically repair code: https://www.cs.virginia.edu/~weimer/p/weimer-icse2012-genpro... . They've also achieved better-than-human level results in antenna design for NASA ( https://ti.arc.nasa.gov/m/pub-archive/1244h/1244%20(Hornby).... ) and in discovering novel quantum computing algorithms ( http://faculty.hampshire.edu/lspector/pubs/GP-quantum-GP98-w... ).

I'll also shamelessly hock here my GP framework for Python, in case you're interested in experimenting: https://github.com/hchasestevens/monkeys

A couple of years ago I read about some printer manufacturer evolving the shapes of their nozzles. Apparently the problem was nontrivial and rather than doing complicated analyses up front they found it more efficient to simply generate and fabricate random permutations of shapes and evolve them over many generations. The results were better than any human designed ones, apparently.

It's just a toy, but it's pretty entertaining to watch:

http://boxcar2d.com/

Unfortunately, it requires Flash.