My first thought on seeing xkcd's take on the tar command was "Is he creating an archive or extracting one? And is it gzipped?" ;)
The second thought was "Wow! All those years of compiling from source have payed off!"
(for the record, "tar -xzvf <filename.tgz>" will extract a gzipped tarball, but because of the first two thoughts, took slightly longer than 10 seconds to recall)