Run the application setup, select the (Paid) edition of Quartus II and/or ModelSim-Altera.
Wait for it, or take a lunch break...

When asked for a license, cancel the dialog box.

Unzip the crack into the install dir e.g. \altera\11.0sp1\ and overwrite folders/files.

Run the LicenseMaker.exe from the install dir with administrator privilege.
It will create a license.dat and set the required system environment variables
LM_LICENSE_FILE and MGLS_LICENSE_FILE which point to the location of the license.dat 

Launch the program.

When asked for the license, select the option to specify valid license file,
and "Use LM_LICENSE_FILE variable" (or browse to the license.dat)

You can do the same procedure (or verify the license status) from the program
by going to the "Tools", "License Setup".

Enjoy.