Meaning odd, strange, vaugely amusing in a weird sort of way, wacko with somewhat something of a benign twist. Malevolent things of this nature are generally called creepy or are said to raise hair on the back of one's neck. I've no idea where this expression came from.

Off the Wall was an album by Michael Jackson. Most of the songs were written by Rod Temperton, of Heatwave fame, so the album has a disco feel to it. The title song sounds a lot like Heatwave's Groove Line.