VI keymapping

Generally, all I tend to use this for is adding or removing comment characters to/from large blocks of code. The most recent example sequence for setting up the map is:

:map ~ 0i%j

Here is a link to the subject stuffed with extraneous info that I didn't need to remind me of how to do this:

http://vim.wikia.com/wiki/Mapping_keys_in_Vim_-_Tutorial_(Part_1)