This Etsy seller took the "trash the dress" concept to a whole new, awesomely crafty level. From the Etsy listing:
Handspun Art Yarn from my wedding dress — UpcycleBB Contest Entry — take something no longer useful and upcycle it to a higher purpose…One (1) 16 yr. old size 8 country tulle style wedding dress. Cut into long thin strips and scraps using sewing shears. Handspun into singles on a foot operated spinning wheel. Plyed on a drop spindle. No other material used. Transformed into 181 yards of useable art yarn.
(Thanks for the heads up, Marie!)