Gaston Acurio is one of the best chefs of Peru. His ceviche is amazing. He has a restaurant in Peru called "La Mar", whose ceviche really impressed me. Anyway, he has a franchise in SF now.
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/09/30/FDJK13892R.DTL Eat there! Tell me if it is delicious, and I'll go eat there if I make it to SF in December.
Peruvian Ceviche, for the uninformed, is raw fish, preferably sea bass, "lightly marinated" in lime juice for a couple of minutes. Go try, if you are a raw fish aficionado. :)