Yes. Mine suffered a similar fate last weekend. Did you move it recently? Or if its kept vertically was it knocked over? The early xb360s (like mine) were notorious for bad solder joints. Last weeks issue had me going over the mobo with Fluke in hand testing voltages, though I didn't find anything. Then when I placed it back in the chassis, the damn thing booted up as if nothing had happened. AND I was able to download the blades of time demo (the cause of it all) without any further issues.
IMO these things are very temperamental, I've already placed an order for a 4GB slim model because I'm tired of the anxiety this thing causes me whenever I power it up. Also have you done xclamp mod? If you haven't suffered the RROD yet, you will eventually, so might as well get that done, it's especially useful in our climate.