Narrative:

Upon landing at mem, we realized we had never contacted the tower for landing clearance (approach control never turned us over). My feeling tired and therefore not totally alert, was a contributory factor. Some kind of ritual that the PF and PNF each go through to confirm landing clearance prior to every landing is essential. I have my own ritual when I am the PNF reading the checklist, but don't go through the same ritual when flying. I will now always go through the same ritual whether I am flying or not.

Google
 

Original NASA ASRS Text

Title: LANDED WITHOUT TWR CLRNC. FLC WAS STILL ON APCH CTL FREQ AND FORGOT TO CALL TWR FOR LNDG CLRNC.

Narrative: UPON LNDG AT MEM, WE REALIZED WE HAD NEVER CONTACTED THE TWR FOR LNDG CLRNC (APCH CTL NEVER TURNED US OVER). MY FEELING TIRED AND THEREFORE NOT TOTALLY ALERT, WAS A CONTRIBUTORY FACTOR. SOME KIND OF RITUAL THAT THE PF AND PNF EACH GO THROUGH TO CONFIRM LNDG CLRNC PRIOR TO EVERY LNDG IS ESSENTIAL. I HAVE MY OWN RITUAL WHEN I AM THE PNF READING THE CHKLIST, BUT DON'T GO THROUGH THE SAME RITUAL WHEN FLYING. I WILL NOW ALWAYS GO THROUGH THE SAME RITUAL WHETHER I AM FLYING OR NOT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.