This is an excellent, quick, beef noodle soup that never fails to please. It is adapted from Jennifer Brennan's Original Thai Cookbook. For the noodles, try to find packets of wet noodle sheets. These can usually be found in Asian groceries, refrigerated, in clear plastic bags. If you can't find these, you can substitute dried rice noodles, but soak them first. The fish sauce is the Thai Nam Pla sauce, or Tiparos, found in the Asian section of supermarkets, or in Asian groceries.