Wikipedia: Friday the 13th
Detailed article about the day Friday the 13th, the date often considered to be a day of bad luck. Includes calendar of upcoming Fridays the 13th.
Friday the 13th, 2029
Read about how Asteroid 2004 MN4 will come scarily close to Earth on Friday, April 13, 2029, typically considered an unlucky day. Also listen to Dr. Tony Phillips of Science@NASA talk about the occurence.
Friday the 13th Phobia Rooted in Ancient History
National Geographic article examines people's fear of the number 13 and possible cures for the phobia called triskaidekaphobia.
HowStuffWorks: Friday the 13th
Attempts to explain "how Friday the 13th works," the phenomenon of paraskevidekatriaphobia, with information about the Christian and other traditions.
Friday the 13th Origins and Myths
Looks at why Friday the 13th is considered the unluckiest of days in many superstitions. Includes Norse legend, biblical, and Knights Templar references.