If you're a heavy sleeper and have trouble waking up in the morning to your phone's alarm, Redditor tribalwombat discovered you can boost its volume by sticking it in a drinking glass.
This works because the sound will reverberate inside the glass. It may not be the world's most pleasant amplification technique, but it works great for an alarm. On top of that, to turn the alarm off you have to actually pull the phone out of the drinking glass. This makes it a bit tougher and makes it just a little more likely that you'll have to get out of bed.