How can I install MacVim on OS X?

Question

I am using OS X 10.9.1 (Mavericks).

What are the systematic steps to install to Gvim or MacVim in Mac OS? If you write the steps using 1, 2, 3, ..., it would be easy

Answer 1

There is also a new option now in http://vimr.org/, which looks quite promising.