In case anyone was wondering, I am keeping the default US time zone since most of the challenges come from the US - this makes it a bit weird for those of us on the other side of the world, as the day is pretty much over before the new challenges are posted :P
Of course, while I have grouped the challenges under days of the week for convenience, nothing says that a challenge has to be answered on any particular day... I think a challenge should be open until a new one replaces it on the site where you found it... I guess you can even do challenges that have expired if they appeal to you :P
The rules are there are no rules! Except to have fun...
(I'm only writing this so I can post at 1am and see what time that means in 'Blogger time' :P)