Tip of the hat? Air kisses? Sniffing each other's butts like dogs? Singing a song detailing your lineage back to your most famous ancestor?
The United Nations, 1 January 1955:
"What do you mean, we can't swear in the new ambassadors for this year?"
"Because last year's ambassadors are still introducing themselves."
"What?"
"The Israeli ambassador has been singing all year and is only as far back as David. He still has to get back to Adam."
"Huh?"
"The Japanese ambassador has gone through his royal ancestors back to about AD 100, but he has about 700 years to go too until he gets to Emperor Jimmu."
"..."
"Oh, and the Egyptian ambassador is only back to the Twelfth Dynasty. Just be grateful that Egypt only counts back to the First Dynasty and Pharaoh Narmer. If they counted the Pre-Dynastic rulers we'd still be waiting for the 1950 ambassador to finish introducing himself."