My idea is for the City to partner up with local musical groups (possibly from the S.U.B. website promoted on the City of Culture website this morning) and arrange a citywide treasure hunt with musicians performing at each location. Contained in the lyrics (or for the smarty pants in the music itself) is the clue to the next location. 

It may also be a good idea for locations to be near parks, pubs and other areas where treasure hunters who need to take a moment to figure out the clue (or may have simply given up) can relax and ponder the culture of the great steel city.

The entire treasure hunt can be captured on cheap flip cams distributed to registered competitors to generated cost effective and impactful video stories to be featured on the web.