April is the 30th anniversary for Post-It® notes. The invention of Post-It notes began by accident in 1968 when Spencer Silver discovered a unique adhesive that would not only stick to surfaces but also could be repositioned repeatedly. Art Fry, Silver’s colleague, needed a bookmark for his church hymnal that would stay in place while singing in the church choir. Fry applied the adhesive to create a new bookmark and the product was released in 1980.
See www.3m.com/us/office/postit/pastpresent/history.html for the full story about Post-It notes!