Is there a way to download an entire Blogspot blog in HTML format, without the ads and associated cruft?
Just my two cents ... Winhttrack?
Perl has several good modules for doing this.
Both can be found on http://search.cpan.org
From the command line, when this tool is called, you can recursively grab all files in the directory by typing
wget -r sitename.
As for out of the box software that you can use on a GUI, I am of no help.
For the owners of the blog... Google provides the functionality to download the entire blog (posts, comments, the whole nine yards).
In case of content from other people's blog, copyright violation comes into the picture.