I´ve had two 360´s so far, only one had the Red Ring twice.
I bought my first 360 in 2007, it was pre-owned, it was originally bought in 2005, one of the first.,
The first RROD was in Jan 2008, i still remember that it was in the week of the Turok demo.
It was still under warranty, so i send it to MS.
It returned two weeks later.
In Sep 2008 i took the Xbox from where it was (dining room, connected to my PC monitor, with very good airflow to it) and set it on the living room, on a shelf, connected to my LCD, with much less airflow.
Two months later, it had the RROD once again.
I sent it to MS for the second time, and when it returned, i sold it.
I bought a new one after a few weeks with the money i made from selling the other and a little more (it was my idea from the get go).
1 month later, in Jan 09, i had the RROD....for 20 minutes.
I turned the Xbox on and i the red ring came to life.
I turned it off, and tried it again 20 minutes later and it worked,,,perfectly, and since then it´s working like a charm.