Seems like the easy solution is one of those solar systems marketed as being for camping, right? Not sure it's economical, but easy.
Personally I'm interested in a DIY mod to add solar panels directly to the back of a laptop screen. It probably wouldn't be able to actually charge unless the machine is in sleep mode (which also would have the lid closed which would help), but it would extend the battery - if the machine averages 10W and the panel gives 1W, that's an extra 10% runtime for free, and better if it sleeps in the middle (which works, because I'm unlikely to use a laptop continuously for 10 hours).
Personally I'm interested in a DIY mod to add solar panels directly to the back of a laptop screen. It probably wouldn't be able to actually charge unless the machine is in sleep mode (which also would have the lid closed which would help), but it would extend the battery - if the machine averages 10W and the panel gives 1W, that's an extra 10% runtime for free, and better if it sleeps in the middle (which works, because I'm unlikely to use a laptop continuously for 10 hours).