If you're one of the folks receiving the tax rebate from the government this month, and you've been wondering what to do with the cash, consider this: Give For Change, a website which allows you to make "online donations to causes you care about," will match your $300 or $600 donation (up to a million dollars) to any non-profit. If you'd been considering donating your refund, this looks like a great way to increase the impact of your gesture.