> Make sure the sighted friend wears the blindfold too to make it a shared experience

Thise are good ideas, and this is quite a nice thought.

On a somewhat related note, as far as possible, we try to let our disabled daughter experience age-appropriate activities that her peers engage in (even if they have to be modified somewhat). This models good behaviours for her, and often helps encourage her to do things she'd otherwise be unwilling to eveb try, for fear of failing.