Lance has a great post about meeting people and how to identify other interested parties. He came up with The Inqueery Gesture, a shoulder shrug (SYN) followed by the confirmation by lip lick (SYN,ACK) or denial by scowl (NAK). Nothing to close the handshake like sequence though, maybe walking away could represent the final FIN. His concern is meeting other men, which doesn’t apply to me (actually meeting women doesn’t apply to me either anymore, but that’s besides the point), but I’ve long proposed that a system is needed for everyone (especially geeks) to find out if they are interested or not quickly and without the embarrassment of actually talking to them.
My idea, years ago now, was that everyone gets a little LCD implanted in their forhead that has vital information like sexuality (straight/gay/bisexual), mental state (psycho/not psycho), relationship state (single/attached/undecided) (very important this one IMHO) and interest level (interested/not interested/you are a toad).
The one downside of this would be that everyone would have an LCD implanted in their head, but I think the benifits would far outweight the disadvantages.