Whether it's plain old HTML or freakishly advanced ruby on rails, ask for code samples. Source code can say more about a persons work habits than you think. Clean, elegant code can often be indicative of a methodical, capable developer. A resume may say 6+ years of perl experience, but that could mean 7 years of bad, unreadable perl. Also, make sure you ask for a lot of source code, not just a few isolated functions or pieces of HTML. Anyone can clean up 20-30 lines of code for an interview, you want to see the whole shebang. Don't ask for a full, functional app, but make sure it's enough that you can tell it's really what their code is like.