enable sudo with root password

# apt-get install sudo (for debian users)
# visudo -f /etc/sudoers (open the file for modifiation)
add the following to the file
Defaults env_reset, rootpw
yourusername ALL=(ALL) ALL

Now you have a working sudo which will ask for root password instead of user password at the time of running sudo.Gives a feel-good feeling of entering super user password before running super user commands.