If there are undiscovered passageways and rooms in the Sphinx, Zahi Hawass is the man to find them; the renowned Egyptologist has already cleared two tunnels inside the enigmatic structure and located two previously unknown nearby pyramids. In a slide-illustrated lecture, “Tunnels and Secret Passages of the Giza Pyramids,” Hawass will address these mysteries. Using information from the latest excavations, the archaeologist will also discuss the history and purpose of the pyramids and the Sphinx. At 8 p.m. at the Department of Agriculture’s Jefferson Auditorium, 12th & Independence Ave. SW. $16. For reservations call (202) 357-3030. (MJ)