 Apple's OS X is off big cats and onto California locations. While many predicted that it would be either named Lynx or Cougar, Apple decided to call it Mavericks.
Coming this fall.....

• Apple Rolls Out OS X Mavericks With Tabbed Finder, System Tags, And Improved Multiple Monitor Support | TechCrunch

• Apple OS X Mavericks gallops into view | Apple - CNET News

In pictures : Getting to know Mac OS X 10.9 Mavericks (pictures) image 22 - CNET Reviews

I don't like the name but it really doesn't matter to me what they call it.

iOS 7 is also coming this fall with a completely new design. It really looks very cartoonish to me and I am not sure if I will like the new design.
What I personally like is the Control Center, Air Drop, Find my iPhone activation lock, automatic app updates and the new interactive weather app.

Apple - iOS 7