Lewis-Harris hidden gems?

Hubby and I are taking a trip to the island in August as part of my Masters in Architecture, and although part of the trip will include accumulating information with regard to a site for my theoretical project (currently I'm hooked on Tarbert as a location), a large proportion of it will be spend soaking up the atmosphere and the kooky nature of the island (think Jonathan Meades' 'Island of Rust').

So....does anyone have anything to share?... any must-see recommendations for things to do? Any hidden gems?

Look forward to any replies,
Sarah xxx