What does getting the "Red ring of death" on the xbox360 only once mean?

Just tonight i played my 360 for 5 hours straight for the first time in about a year… i pressed the power button to turn it off…. TV went blank but the green circle on the 360 turned red. Worried, i pressed it again and the xbox turned back on and the tv came to life… The 360 worked fine. i pressed the button again and the system shut down normally.

Does this mean anything?

EDIT: I just got the red ring again after turning it off for an hour… i turned it offand back on and it works properly again