While there are some complex things you could do with it, for this problem, you shouldn't need much more than writing out the same commands you would give on a command line, plus a few variables.

#!/bin/sh
date=`date +%Y%m%d%k%M%S`
path=$1    # Path to use is given on the command line

# Use last directory in ${path} as the filename to save 
# to.  (Could use awk or something else here, but I'm 
# more familer with Perl).
# 
save_file=`perl -e '$file=pop; $file=~m!/(.*)$!; print $1' ${path}`

tar -zxf ${save_file}-${date}.tar.gz ${path}
[download]

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I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated