sending git patches

[Graham Percival]

Suppose that a nice helpful GDP helper has git working.  They make some 
changes, commit stuff, make more changes, commit more.  Now what's the 
best way for them to send these changes to me?

(assuming that they don't have write access to the repository)

I know that git has a huge number of git-diff options; what's the best 
option in this situation?

Cheers,
- Graham