The Bitcoin Faucet will give bitcoins for free to each visitor. It is operated by Gavin Andresen.
The bitcoin faucet will give out varying amount of bitcoins per visitor, depending on the amount of bitcoins in the faucet account. Currently, when there are less than 500 bitcoins in the faucet, it gives out 0.05 bitcoins, or 0.50 bitcoins otherwise.
The bitcoin faucet will also provide test bitcoins for people who want to do tests on the testnet.