Scheme: Graph lines of code in Subversion
This checks out every tenth version from SVN and produces a data file which can easily be used as input to gnuplot. You can see the final graph.
(module foo
(main main))
(define *new-test-regexp* (pregexp "^[ \t][ \t]*void\\s+test[A-Za-z_0-9]*\\s*\\(\\s*\\)"))
(define (is-test-header? filename)
(cond
((not (string-ci=? "h" (suffix filename)))
#f)
[...]

