May 25, Towel Day
Towel Day is celebrated every year on 25 May as a tribute to Douglas Adams. The commemoration was first held 25 May 2001, two weeks after Adams’ death. Some fans registered the domain name http://www.towelday.org and it was an immediate success.
In May 2010 an online petition was created asking Google to recognize Towel Day with either a Google Doodle or by returning search results in the Vogon language for a day. Although 5,373 signatures were collected Google has not done either, as far as I can tell.
On Towel Day 2015, astronaut Samantha Cristoforetti sent a “Towel Day Greeting” and read aloud a sample from The Hitchhiker’s Guide To The Galaxy from the International Space Station.