Just to be a little bit devil's advocate....
The people saying to fix it up and donate it are being quite generous with your money and time. If you're not a tinkerer, getting a bass set up can be a not-negligible cost, not to mention the price of strings and any necessary parts.
But what, one may ask, is the cost of a set of strings or a couple pots against the opportunity to provide a start to the next Stanley Clark (or whoever)? Well, it's still money out-of-pocket. That's a slippery slope. Perhaps some of the people so quick to say to do a bunch of work on the bass and donate it would be willing to front the cost of shipping so they could do the work and donate it? Shipping ain't cheap, but again, what's that cost compared to the warm fuzzy feeling you get at the end?
And there's another factor: from this thread, you'd think that every piece of crap old junker bass is some neglected jewel that could be an amazing inspiring thing, but, it should also be acknowledged that a bad instrument can actually dissuade a curious kid from playing. Donating a PoS that's hard to play, ergonomically challenged, ugly, broken, etc. to your local kids music program is not automatically doing them any favors. There may be that one kid who will work through all the shortcomings of the bass because he or she is so passionate about it, but far far more likely is the scenario where a kid gets a bad bass, doesn't enjoy playing it, and ends up not pursuing bass.
"Fix it up and donate it" is by far the most noble course of action, if you can fix it up yourself and want to, or don't mind spending that money, but if it's a real stinker I don't think there's any shame in taking it out of the bass gene pool, as it were. Some people have mentioned programs that will fix the stuff up themselves, and that might be a good option, if you can find one of those. But I don't think anybody should be expected/required to front a bunch of money in order to get a trashed old PoS instrument out of his house.