So you've gotten into a furious argument with a Lithuanian, but you can't come up with a crushing ethnic insult. Hold your tongue no longer, for here is the Racial Slur Database, which proves that the peoples of the world are truly united, if only in their hatred of each other.
"Lit" or "Balt" or "Litvok" should do the trick. Never let it be said that this blog isn't educational.
Update: The people, er, person has spoken. Henceforth email notification on comments will not be sent out.