Came across this interesting blog by the Mathematical Association of America, titled
NumberADay.
http://maanumberaday.blogspot.com/They post a number everyday, and also discuss the significance of that number and its properties. I found some of them quite interesting.
[Edited the post to make it a 'Linkin Park' kind of thread. If you have interesting links to post, please post it under this thread. Such posts usually don't attract much discussion, so it is better not to create a separate post for each link. In case there is a potential for discussion, one can always fork a new post. -- Sanket]