On to masculine rooms. Here’s what I’m going to say: leather. Dark tones seem to be awfully popular for these interiors and I have to say the tend to work quite well. Lighter tones can also work but I would avoid all bright colors besides cobalt blue. Tweeds, plaids, herringbone and houndstooth. I don’t even know what accessories one would decorate a man room with? Leather bound books and journals? Cigar boxes? I would say keep décor simple and straight forward and also sparing. Brass lamps perhaps? Otherwise, enjoy the man cave.