What do Gaels, Gauls, Galicians, and Galatians have in common? They were all related names for the Celts, members of a civilization that once stretched from Ireland (Gaels) to France (Gauls), Spain (Galicians), and Turkey (Galatians), dominating Western Europe before the Romans complicated their lives. Ferocious warriors who sometimes engaged in a spot of human sacrifice, the Celts also included adroit metalworkers and lyric poets, and had an unusually egalitarian system for their time. Oxford University archaeology professor Barry Cunliffe will explain more, in a slide-illustrated lecture based on his book, The Ancient Celts. Celtic culture is still being excavated and analyzed, but one thing is clear: There’s more to it than some Riverdance. At 8 p.m. at the Museum of Natural History’s Baird Auditorium, 10th & Constitution Ave. NW. $13. For reservations call (202) 357-3030. (MJ)