Recently I've been writing up an article for one of the Elsevier journals using their elsarticle LaTeX package. Unfortunately, their BibTeX style file, elsarticle-num.bst (version 1.1, 2008-10-13), is a bit broken. With the help of Nicolas Markey's excellent Tame the BeaST, I've fixed it up so it runs without errors (!), works with natbib's \citet{}, and conforms with the examples posted in the International Journal of Biological Macromolecules' author guide.

Update: Oct. 6. Turns out the code linked from Elsevier is out of date. Rishi over at River-Valley (writers of the elsarticle package) pointed me to some more up to date documentation and source. Version 1.2 fixes most of my problems (with elsarticle-num-names.bst), but I'm still not sure why it doesn't replace elsarticle-num.bst entirely...