Solar Showers

Coleman 5 Gallon Camp Shower - Coleman is a respected name brand, and this one is simple and sweet - a little bag that expands to hold five gallons of water. It uses solar energy to heat it up, letting you avoid a cold shower - a little spray hose lets you use it. It's obviously not ideal compared to a bath at home, but it works. It's also cheap - about $10 and you can get it online here.

Sunshower Portable Solar Powered Shower Bag- This operates on the same concept - leave it in the sun for a few hours and the water inside gets hot. It holds 2.5 gallons. It's also pretty durable. It costs $21 and is available online here.

Paha Que Power Shower - This is the same concept but it uses a 5 gallon bucket instead of a bag. That has the advantage that it's much less likely to break, because a bag can just get a hole in it easily. It's also pressurized, so you can get a better water flow than with one of the cheaper bags. It has the disadvantage that it is bulkier and you can't compress it when there's no water in it. It might be a better option for you if you've got the space - but it's also more expensive, around $90. It's available online here.

Battery Operated Solar Shower - This one is still solar-powered in terms of heating up the water, but it uses batteries to power a pressure pump so you can get an actual spray of water going. It's sort of a middle-ground between the cheap bags and the expensive ones. You'll have to get the batteries separately. It holds 3 gallons, and it's available online here.