ATV completely shuts off while riding it?

So i was out trailriding today on my atv, (it was cold, but not that bad at about 30 degrees farenheight) and after I got up a small hill, my ATV (a honda 250ex) completely shut off. I tried to put it back in neutral but it wouldnt shift down, but eventually after i got off and gave the quad a little push, it went down to neutral. This has never happened to me before, and i have had never had one problem with the quad for as long as i have had it. Does anyone know what is wrong, and if it is a significant problem?

Added (1). I had a full gas tank, and the oil level is fine. After i got it in neutral, i was able to start it and ride it back home no problem. Just wondering if this is normal or not.

All you have said is it wasn't that cold and you never had this happen before. Do you think you could check the fuel level and maybe if it has spark before you come on here asking with no information.