Why isn't my phone turning on?

I was at a party and i had just taken two pictures when my phone just shut off. Not the usual, shut down kind of way it just immediately became black. I had not dropped it that day nor was its battery extremely low as it was at 50 percent. I decided to leave it alone until the end of the party. When i came back home i tried putting it on but nothing happened. I even took out the battery, checked to see if there was anything wrong and put it back in. It didn't work. I left it on charge the entire night and i checked again this morning but it still isn't turning on. Has anyone experienced the same problem? (this is the first time this has happened like this)