This little tool calculates ABC metric for your Ruby code. Requires Ruby 1.9 but should work more or less with sources compatible with 1.9 and 1.8.
$ gem install metric_abc
$ metric_abc filename1 [filename2] ...
Output from metric_abc is in form of:
where SCORE is a number. The higher SCORE is, the more crazy code is. If a method scores above 20, it very likely needs some refactoring because it's complete shit.
method is not always properly recognized, sometimes it's full of shit like #@const#1#5#@const etc. Need to look at AST to figure out what's wrong