An inscribed cup has been found in Alexandria that dates to 1st century CE and supposedly bares the name of Christ: DIA CHRESTOU OGOISTAIS.
This find was first reported in the German newspaper Der Spiegel. The paper asks if this is the oldest witness to the existence of Jesus of Nazareth although sceptics are interpreting the cup as referring to a common name and OGO as some kind of cult. In any case a very interesting discovery and hopefully more details will surface in the coming days.
UPDATE: Thanks to Tom Elliott for posting link in comments for up to date info and discussion on the inscription.