Eton has a bit of a thing for music plus solar power. We're not complaining though. Its latest eco-powered music machine is the rukus Xtreme, and brings potentially non-stop daytime jams to the great outdoors. The Bluetooth (4.0) device has five speakers (two main, and the rest for "bass radiating") and has a built-in 6,600mAh battery than can be charged either by Mother Nature (in around five hours), or a good, old outlet (in three). Either way, you can use that juice for prolonged listening, or use that battery to power up your phone/tablet -- so it's effectively a solar charger too. There's NFC for easy pairing, and you can even link up two units for, well, we imagine, Xtreme loudness. The IPX4 water-resistance rating also makes it good for those who like to dance in the rain, and frankly, who doesn't? The rukus Xtreme will be ready to soak up those rays come springtime, costing $230. There's also a rugged rukus II model for $130, if you don't need quite so much onboard battery (1,600mAh instead).