Well, if Google isn't lying to me, this isn't paranormal. But still the most terrifying experience of my life. Just yesterday.
I hadn't slept for two days because I'm an idiot, and school is coming back tomorrow, so I'm kind of stressed (I hate school). Combine this with the girl I like rejecting me, and my mental and physical state is about at it's lowest. I was trying to sleep and dozed off, but woke up just a little bit later because someone texted me and my phone was right next to me. I replied (something to the effect of 'Jesus, it's like 4am and you woke me up. Thanks, dood') and tried to go back to sleep. Then, an extremely loud noise filled my hears and scared me so much that I swear my heart nearly exploded, and yes, I cried out.
The noise was like... imagine a god damned Viking ROARING in my ear. It only lasted for a moment, and that was enough to make me cry out and jump out of bed, then not sleep for a few hours.
Google told me this might have been something called (I shit you not) "Exploding Head Syndrome", which is basically a severe auditory hallucination, possibly being brought on by stress and fatigue. I was definitely stressed and fatigued. Still am, really.
Moral of the story, sleep well and try not to get stressed out, or you might get EXPLODING HEAD SYNDROME.
Link to exploding head syndrome- I'm not making this shit up, guys: http://en.wikipedia.org/wiki/Exploding_head_syndrome