Do you have Netflix? It's discussed in the 'Chefs Table' doc on Grant Achatz in season one.

The whole idea of the restaurant is to push the limits of what a meal is and part of the way they do that is to challenge what is possible. They have served food on a pillow filled with pine scented air so when you eat the dish the pillow puffs the scent into the air, changing the flavor of the dish.

It is indeed cerebral food and not for everyone and that's OK.

As to the balloon:

He said that since 2005 they had been trying to come up with a way to make food float. “How could we do this. Do we embed things in the table surface? Do we use a magnet? It took us seven years to find how to make it. We created something which is on the borderline of unachievable. Sugar’s worst enemy is water but here we mix it to make it work. The amount we use depends on the humidity. We have 25 variations of the recipe depending on the weather and humidity. We made an edible string with apple to tie the sugar balloon. In 2005 we challenged ourselves with an impossible idea. It took us 7 years to find the answer. Sometimes we joked about it and time and time again we took what we learned and advanced a bit further. Then I was in France and received an email from a chef telling me we got it. I asked whether it tastes good. He said yes chef.”

Alinea serve the balloon which is sugar blowm with helium as part of the tasting menu. This is served as the course before the last. “Our idea of a restaurant is to make people laugh and to feel relaxed. We want to create texture and emotions. We want to take it a step past just delicious food. My idea is to connect with people. If I can make my guests laugh, then that is a huge achievement,” he said.

Here's a video they made for a conference. Enjoy.

https://www.youtube.com/watch?list=UUprPL2xor8Wr87XPQiuM6bw&v=8EK6Ps-ujHc