|For those not familiar with what the 24 hour challenge, you can always google it.
Or...you could tell us.
He mass-posted that to all his things like deviantart, livejournal, and facebook.
A 24-hour comic is a 24-page comic book written, drawn, and completed in 24 hours. Scott McCloud originally came up with the challenge for himself and Steve Bissette as a creative exercise. McCloud drew the first 24-hour comic to prove it could be done on August 31, 1990, and Bissette did his on September 5.
Word of the challenge slowly spread, especially as Dave Sim started publishing his own 24-hour comics in the back of his popular Cerebus the Aardvark. Eventually Scott McCloud had collected six 24-hour comics on his website from different, well-known comic-creators. Creators Erik Larsen and Chris Eliopoulos published their 24-hour stories together in the one-shot comic Image-Two-In-One featuring The Herculean and Duncan ("The Herculean" being Larsen's creation, and "Duncan" being Eliopoulos').
As originator of the challenge, Scott McCloud has established rules for a comic to qualify: It must be begun and completed within 24 consecutive hours. Only one person may be directly involved in its creation, and it must span 24 pages, or (if an infinite canvas format webcomic is being made) 100 panels.
The creator may gather research materials and drawing tools beforehand, but cannot plan the comic's plot ahead of time or put anything on paper (such as designs and character sketches) until he is ready for the 24 hours to begin. Any breaks (for food, sleep, or any other purpose) are counted as part of the 24 hours.
If the cartoonist fails to finish the comic in 24 hours, there are two courses of action suggested: Stop the comic at the 24-hour mark, or continue working until all 24 pages are done. The former is known as "the Gaiman variation" after Neil Gaiman's unsuccessful attempt, and the latter is called "the Eastman variation" after Kevin Eastman's unsuccessful attempt. Scott McCloud calls both of these "noble failures", which he will still list on his site as long as he believes that the creator intended to finish the project within the specified amount of time.
To be officially recognised as a "24 hour comic" or a "noble failure", the cartoonist is required to submit a copy of the resultant comic to Scott McCloud.