In March 2006, Bob Floyd posted a Sunday Mystery Object. It was something simple, looked at in a new way, which made an interesting photograph, and was also not obvious as to what the item was. You can see it here. I loved this kind of thing. Occasionally, Bob would post another Sunday Mystery Object and I would have fun all over again looking at some cool photo and trying to figure out what the item was. For quite some time, I badgered him about making this more of a regular occurrence. Finally, I suggested we could make a game of it and I'd play along with him. And thus the Monday Mystery Object was born.
Why did it change from Sunday to Monday? Probably because I messed up and forgot that his original mystery objects were always done on Sundays. Perhaps because "Monday Mystery Object" has more alliteration to it. Whatever the reason, here's my gallery of Monday Mystery Objects.
Answers to what each mystery object is can be found in the MMO Answers gallery.