Date: May 25 Origin: Two weeks after "Hitchhiker's Guide to the Galaxy" author Douglas Adams died in 2001, fans online proposed commemorating the writer's untimely passing by carrying a towel with them everywhere. The towel, as any reader of Adams' comedy sci-fi novels knows, is the universe's most indispensable item. The website TowelDay.org has become the central hub of all Towel Day news and info. Pictured: Sam Rockwell, left, Zooey Deschanel and Mos Def in movie "The Hitchhiker's Guide to the Galaxy." Disney Enterprises Inc.