Rake as a library, from anywhere in the filesystem

gistfile1.rb

#! /usr/bin/env ruby

require 'rubygems'
gem 'rake', '>= 0.7.3'
require 'rake'


Dir.chdir('where/I/want/to/be')

Rake.application.init('my-script-name')

# Tasks go here

Rake.application.top_level