I stumbled on these posts on AVEN here and here, talking about wearing a black ring on your right middle finger as a sign that you are asexual.
I like the idea of increasing visibility, especially among each other. I went and bought myself a nice-looking but inexpensive black band off of Ebay. And although I don't expect to be seeing large numbers of people sporting black ase-rings just yet, I want to support this as I'm hoping that the symbol will penetrate public awareness over the coming years and make it a little bit easier to exist as a legitimate minority. So this post is kind of an encouragement to spread awareness for all those who wish to pick it up. Wear a black ring on your right middle finger when you want to claim an asexual identity. Tell everyone who is interested in your ring, and let them know that this subculture exists. I'd complement this with the "ace of hearts" symbol where appropriate.
Hopeful vision of the future: guy tries to romance girl who seems to be playing hard to get. Guy checks her left ring finger. Nothing. Then guy checks her right middle finger. Guy sees black ring. Guy knows and understands that this means she is not interested in sex with him, thank you very much, and does not take it personally. People do not pressure you with questions and expectations about getting together with someone, or getting married, are not continuously suspicious of your permanently single status. The hope is that maybe one day asexuality would become at least as commonplace and accepted as being gay is today.