Groping for words (or the expanding universe and metaphorical problems)

What's funny is that this is just a short post about how I'm having trouble these days coming up with good metaphors. I was trying to describe expansion (in relation to my waistline, unfortunatley) and spent five minutes trying to come up with something better than 'like a balloon' or 'like the universe'. The first one is overused and the second is pretty obscure. I would bet that no more than 1 out of 10 random people you asked would know the universe is expanding, not unlike my belly, though I'd say that my belly is markedly less studied. Hopefully.

By the way, the picture is of the galaxy M100. The Spitzer telescope (currently orbiting about 520 miles above the Earth) took this picture. It shows how the universe is expanding by observing distant lights in other galaxies and monitoring how fast they move away from other objects. By measuring the distance they travel scientists can find out how fast the universe and everything in it is spreading. Freaky!