Here are a few links to some folks who have devoted their lives to the idea of the spectacle. They run the whole gamut from world-class artists to, well, a guy who tied weather balloons to his chair and flew to 30,000 feet. I'm not advocating any of their acts, but simply giving you some examples of what has caught our collective eye in the past.
So this pales in comparison to Petit's run across the wires, but I include this video of derring-do in honor of my collegiate years spent in the Nattmosphere and as an example of probably the most well-thought out plan ever to involve Natural Light.