From the outside, exhibit conference rooms often comprise little more than opaque – and uninteresting – walls and doors. Like old-time speakeasies, these nondescript exteriors offer few clues as to the elegance and excitement often housed within. However, if secrecy isn't a serious concern for client meetings, why not add a little flair and make your conference room's exterior a bit more inviting, not to mention a whole lot more interesting? Featuring everything from colored Plexiglas to inflatable walls, these six conference rooms offer a fresh take on otherwise tedious exteriors. By Linda Armstrong