Say the words “theme bar,” and what pops into most people’s heads is a loud, obnoxious T.G.I. Friday’s or Chevy’s-style joint, where tacky decorations crowd the walls and sheepish college kids wearing costumes they'll regret for the rest of their lives serve cloyingly sweet drinks in gallon-size bowls. But discounting all theme bars does a disservice to the many fun, innovative wateri...