If you have an adventurous streak, you can grab a "mainline" kernel source tarball from http://www.kernel.org/pub/linux/kernel instead. In this directory, you'll find the official kernel sources, as released by Linus or Marcelo. They may not have all the features found in your distribution's kernel source package, so it's generally best to not use a mainline kernel until you feel that you know what you're doing...or until you have an "extra" machine and lots of spare time :)

At kernel.org, you'll find the kernel sources organized into several different directories, based on kernel version (v2.2, v2.4, etc.) Inside each directory, you'll find files labelled "linux-x.y.z.tar.gz" and "linux-x.y.z.tar.bz2." These are the Linux kernel source tarballs. You'll also see files labelled "patch-x.y.z.gz" and "patch-x.y.z.bz2." These files are patches that can be used to update the previous version of complete kernel sources. If you want to compile a new kernel release, you'll need to download one of the "linux" files.