Dylan started with an s-expression syntax. For several years, it looked like Scheme with CLOS bolted on top. The language eventually switched to a conventional

Dylan started with an s-expression syntax. For several years, it looked like Scheme with CLOS bolted on top. The language eventually switched to a conventional infix notation. It actually looks pretty good to my s-expression-addled eyes, except that "end" blocks explicitly describe the block being ended, e.g., "end if", "end class", "end function". (To any Dylan experts in the audience: if that's optional, feel free to correct me.) Dylan has not exactly failed, since it still has an active development team which makes regular releases, but it has not achieved popularity. Dylan has macros, a real condition system, and a CLOS-type object system --- a way better feature list than Ruby's or Python's, IMO.