bower.json

{
  "name": "foo",
  "version": "0.1.0",
  "dependencies": {
    "bootstrap": "*"
  }
}

Gruntfile.js

module.exports = function (grunt) {
  grunt.initConfig({
    bower: {
      dev: {
        dest: '.tmp/public',
        js_dest: '.tmp/public/js/components',
        css_dest: '.tmp/public/styles/components',
        options: {
          packageSpecific: {
            bootstrap: {
              files: [
                "./dist/js/bootstrap.js",
                "./dist/css/bootstrap.css",
                "./dist/fonts/glyphicons-halflings-regular.eot",
                "./dist/fonts/glyphicons-halflings-regular.svg",
                "./dist/fonts/glyphicons-halflings-regular.ttf",
                "./dist/fonts/glyphicons-halflings-regular.woff"
              ],
              dest: '.tmp/public/fonts',
              css_dest: '.tmp/public/css/bootstrap'
            }
          }
        }
      }
    }
  });
  grunt.loadNpmTasks('grunt-bower');

  grunt.registerTask('default', [
    'bower'
  ]);
};

package.json

{
  "name": "foo",
  "devDependencies": {
    "grunt": "~0.4.2",
    "grunt-bower": "~0.9.2"
  }
}