Watch TV. I suppose this isn't something one should admit, but I relieve anxiety by zoning out with mind numbing television -- stimulating or thoughtful programming is not allowed. :) A couple hours of it usually does the trick.
I distract myself by building Lego Sets. It requires a lot of focus and is quite calming for me. I normally end up forgetting why I was so anxious. They make some small sets called x-pods that even are in their own little carrying case.