Question: So after reading about Blender (A freely downloadable application) [being sold by some company](http://news.slashdot.org/story/11/02/23/0011250/Trying-To-Lure-Suckers-Company-Resells-Open-Source-Blender?from=rss&utm_source=twitterfeed&utm_medium=twitter&utm_campaign=Slashdot) I learned that this is apparently is legal because of the GNU GPL license allows for this.

I'm wondering what exactly constitutes 'code' in this case? Do you also need to include any build scripts or project files? What about resources (or assets) like static logos and images?

Answer: 
There's no rule in the GPL against (re)selling free/open soure software, but the Slashdot article you linked to suggests that this company was obscuring the fact that the code was GPL'd. The GPL clearly states that you have to make the license clear, and make it easy to get a copy of the source.

And I'm pretty sure that "code" in this case means anything you need to rebuild the project, possibly with modifications. However, a project or company can trademark a name or logo (Mozilla famously does this with Firefox) so that no one else can call their fork by the same name.
I suppose the whole codebase is covered by GPL, and selling it does not violate its license (unless you don't *require* to pay), but one who bought it can freely redistribute it then. And you cannot develop software that is not GPL, but is using GPL libraries. See also: [related question](https://stackoverflow.com/questions/1749672/do-you-have-to-pay-for-gnu-gpl-software-that-is-for-sale), [GPL FAQ](http://www.gnu.org/licenses/gpl-faq.html)