The Earned Income Tax Credit--one of the progressive parts left in our tax system. If you have two kids, the IRS pays *you* about 40 cents on the dollar for the first $8,000 your household makes: when a household making $8,000 a year files its income tax return, the IRS pays *them* about $3,000.
The credit is then gradually taken away as incomes rise further. I don't think that the credit disappears completely until you hit household incomes of $28,000 or so. Every household making less than that has its taxes reduced because of this program...
Brad DeLong