Christmas trees made out of balloons are baked. We made one ourselves this year, putting a dab of superglue on each balloon to hold the structure together.
What is not baked, yet, is the idea of putting helium balloons inside the hollow centre of a balloon tree and thereby making the tree float.
According to the link, an inflated party balloon weighs about 1.5g. A helium party balloon can lift about 14g, so that suggests we'd need maybe 8 helium balloons to lift our tree (made from about 70 normal party balloons). Let's round it up to 10 so we can keep a piece of tinsel or two wrapped around the tree. This seems doable, and a floating Christmas tree would make a nice Christmas decoration.
Plus, if your tree is floating, all the more room for presents underneath.-- imaginality, Dec 20 2009 (?) Aerodynamics of a party balloon http://docs.google....2kUZVZd03NkUMAQ4ZnA [imaginality, Dec 20 2009] Balloon tree http://s171.photobu...ent=balloontree.jpgOur balloon tree [imaginality, Dec 20 2009] How did this idea drop like a stone? We need more helium stat!-- 2 fries shy of a happy meal, Dec 26 2012 No kidding. [+]-- Letsbuildafort, Dec 26 2012 Yeah but did you hear about the helium shortage that is expected to happen? I heard it on the news. So this idea is grand, but maybe using more of it's fair share. Oh well +-- blissmiss, Dec 26 2012 random, halfbakery