It's true that one of the benefits of CrossFit is the supportive environment and having people push you, but you don't need a gym to do your strength and conditioning work. Find a friend to cheer you on if you need that support.
Here's a list of body weight workouts:
http://board.crossfit.com/showthread.php?t=38312That "Thug Workout" is actually a really good idea. Here's John Berardi's article on the Playground Workout, complete with a bunch of videos.
http://www.precisionnutrition.com/members/showthread.php?t=7248I do about half of my conditioning workouts at home. I have a couple of medicine balls, a yoga mat, a pullup bar installed in a doorway, a 25 lb kettlebell, and a 35 lb kettlebell. That's more than enough. I also do sprints in my alleyway.