Just finished a playthrough of Proteus, an interesting little indie "non-game" in approximately the same ballpark as Dear Esther (note: it's a big ballpark). Unlike Dear Esther it doesn't have a plot or a fixed world - instead a new island is generated when you start playing, and you just sort of putter around it exploring and interacting with what you find there. Despite the crude graphics, it's really quite charming. It's strongest feature is a procedurally generated soundtrack that responds to what you're doing and where you are, which somehow really helps draw you in. My only real criticism is that I found the pacing just a touch slow. The movement speed is fine, it can just take a little longer than I would have liked between things happening. That said, it only took me a bit under an hour to do a single playthrough.
It won't be everyone's cup of tea, but I definitely recommend it if you're in the mood for a relaxing, smelly-hippy non-game experience.
It's on Steam, or can be bought direct from the developers here.