Ack, I guess you are reading this because you have a bad memory :-)
Stop MySQL service/deamon
sudo service mysql stop
start the safe MySQL daemon without reading the grant tables I.e No passwords are checked.
sudo mysqld_safe --skip-gra… more »
Here are a collection of Mini-HOWTOs some of which are too short even for that grand title. I keep them around as it is easier to remember where to look these up that to remember the content of the mini-HOWTO