Luzinterruptus recently made an installation called 1.000 poems by mail. They filled a garden in Madrid, Spain with 1,000 white envelopes containing poems written especially for the occasion by 17 poets who participated in the poetic festival 2010 Poetas por km2.
The lit envelopes remained hanging in the garden for 3 days, serving as intimate illumination for the festival. The last night, with light still in the interior, they were offered to the public as keepsakes, or better yet, for them to address to a loved one, to whom we would send the envelope.
via http://davidreport.com/201012/1-000-poems-by-mail/