Fwiw an easy way to get started with Grunt & Bower is to clone Bootstrap [1] and follow the setup instructions in the readme. That'll get you up and running with a well-developed Gruntfile.js, Grunt, Bower, Less & JS compilation, testing, and a number of other things. Then you can customize from there with the huge package repository [2] - separate test and prod builds, htmlminification, etc.

[1]: https://github.com/twbs/bootstrap

[2]: http://gruntjs.com/plugins