After having finished a project, I always like to know its actual size. It does not give any value to my work, but it is always fun to see :)
I found this simple command that will pop out the number of lines of code for a given file extension.
cat `find . -name "*.py"` | wc -l
You can also do it for a whole folder
find . -name "*.py" | xargs wc -l