This isn’t rocket science, but surprisingly, it does work. Need your iPhone’s speaker to be a little louder? Drop it into a nice big funnel-top pint glass. The echo chamber effect will pump a few more decibels out of the iPhone speaker and you can still read what’s on your display as well. Great for conference calls or sharing music at a quiet pub.
TUAW adds the tip of putting your iPhone in a ziplock bag when in messy cooking situations but that felt a bit on the obvious side.