Yeah, or jump start the car and let the alternator charge it. You might even be able to put somewhat of a charge on it just by hooking it up standalone to another running car with jumper cables, and let that car charge on it for a while.
I have an ancient hand-me-down charger from my stepdad. It's rusty and looks rough, but still charges just fine... (IMG:
http://www.frrax.com/rrforum/style_emoticons/default/smile.gif) I've thought about hitting the case with a coat of POR-15 next time I have some out.