Thanks to Jay for all the recipes that are in the comments of the first post.
One of the roadblocks to this style of food is that it might seem a little daunting at first. There are indeed a lot of ingredients that one must order, like tapioca maltodextrin and activa, but there are a lot of really cool things you can do with everyday grocery store materials.
Enter soy lecithin and xanthan gum.
Soy lecithin is a soy-based product that is commonly used as an emulsifier and is sold in health departments everywhere as a supplement. Read the ingredients of a chocolate bar the next time you get one and there it will be, keeping the cocoa and the cocoa butter together. Luckily for us, it is used in restaurant settings to create foams and "airs," something you might have seen in menus.
Here is some grapefruit air I just made just using grapefruit juice and soy lecithin, both of which I bought at the Barracks Road Kroger. I just eye-balled this recipe, a little lecithin goes a long way. Simply mix the two ingredients and hit it with an immersion blender until the air collects at the top.
Xanthan Gum is a polysaccharide and thickening agent derived from the fermentation of a certain bacteria. The gum is used in items like salad dressings to maintain the emulsion between oil and vinegar. It is also used in gluten free baking in order to give a similar mouthfeel to wheat-based bread. You can find it in the baking aisles of most grocery stores. I have used it to thicken sauces without reducing them, although one has to be careful about over-using it, as it can create somewhat of a snotty feel if too much is applied. Usually around less than 1 percent of total weight will do the trick.
Unfortunately, I am fresh out of xanthan, but I will post something as soon as I get some more. Until then, look at Sean Brock's blog from Charleston, featuring his restaurant's new biodynamic farm.
PS, this recipe collection put together by Martin Lersch of khymos.org is incredible, take a look at it:
Download hydrocolloid-recipe-collection-v2.pdf