Link to a specific (current) revision on GitHub

To access a single file or directory:

• While browsing directories: Click on the "latest commit <refid>" link at the top of the file list, and then "Browse code" in the blue area near the top.
• While viewing a file: Click on "History" and then on the "<>" button next to the refid to get a link.

Just press y and the URL will change automatically to reflect the current version.

Source

let's say you would like that the someone you send this link

• http://github.com/ripper234/Test-grails-project/commit/c3110a562339a20eaa4c99e25d2e92538bd6c23d

has to work on the resulting code of this commit.

he would do this:

• git clone git://github.com/ripper234/Test-grails-project.git
• cd Test-grails-project
• git checkout c3110a562339a20eaa4c99e
• git branch c3110a562339a20eaa4c99e

now the user has a branch with the code of the mentioned commit.

does this answer your question? -> not sure if I understood it right...