You guys are mean, I almost clicked through until I read the hover-text...
Here is something I actually purchased for myself along the lines of the OP when I need some kind of speaker while streaming pandora from my phone.Premium Portable Sonic Resonance Speaker
# Power: Built in rechargeable lithium battery
# Charging input: DC 5V via mini USB
# Audio input: 3.5mm audio jack
# Output power: 2W RMS
# Frequency range: 40Hz-20KHz
# Duration: up to 20 hours after fully charged
I should probably write the virgin review for that product because it's actually not that bad. All things considered, it's not that bad. Nothing like the tinny/hollow sound you find from almost everything else in that price range.