While I love the Touchlights I posted earlier, I also use a few others, including the Goal Zero "Crush Lanterns" and the Luci Lights. The GZ ones are great to give to people for inside use as long as they can remember to keep an eye on them during recharging as they are not waterproof. The Luci "marshmallow" lights are great for kids as they are waterproof and will take a lot of abuse, you just have to make sure that the kids don't forget and leave them outside charging in windy conditions as they will blow away. I have found that you can set 8 of them in one of the Pepsi 2 liter bottle holders and that keeps them both on the right angle to the sun better, but also keeps them from blowing away.
All of them on "low" will work for days and give usable light.