Works in the same way a book library does, only you're borrowing a bike!
Hop on board to browse through their bicycle books and magazines, enjoy the art gallery and kit yourself out with the latest cycling apparel and accessories. Once you have educated yourselves in the ways of two wheeled transportation, take full advantage of the "bicycle match making service" offered by the "librarians" on board. If you then decide that the bike you have borrowed is the one you wish to spend the rest of your life with, no problem, they sell bikes too!
Sorry Boris, but we think this way of bicycle borrowing is WAY cooler than your Barclay's bikes!
Image © howradmichello