How do you charge a phone without a charger?

I Was at my friends birthday party today at a lake about 45 minutes from my house with a bunch of other people and when I got home I relized I left phone charger there. But I don't want to get a new charger because my mom will make me pay for a new 1 and I don't want a new one because I'm getting a new phone in a couple weeks. I have a razr to so I can't hook it up to my computer with a USB cable because it won't fit on my phones port. So should I just conserve the battery for a couple weeks or is there a way to charge it