Always a good idea: linen teatowls as curtains. Here's a roundup of some recently admired installations.
Above: Photo via Verhext.
Above: For the less motivated among us; an instant curtain idea (via photographer Simon Brown) involving an impromptu curtain rod, a square of linen (doesn't even need to be hemmed), and a pack of wooden clothespins.
Above: Here's a clever idea for creating a casual window covering: tea towels stitched together to make an airy kitchen curtain (especially if you stick to like-colored towels). Photo by Polly Wreford.