I've been planning on making a set of classic games (eg. snake, space invaders...) in Construct for this purpose. I'd probably throw them in as templates. It's a very good idea. Also, if anybody else wanted to make some example games for templates, I'd happily put them in - I plan on having a large collection if possible for the 1.0 release.
Also, you can find the .cap for the 'Rain demo' here
- although I'm not sure if its exactly the same version as on the site. Oh, and the events are a bit of a mess