The CryptoPunks are 24x24 pixel art images, generated algorithmically. Most are punky-looking guys and girls, but there are a few rarer types mixed in: Apes, Zombies and even the odd Alien. Every punk has their own profile page that shows their attributes as well as their ownership/for-sale status.
How do I get a Punk?
1. Download and install a Chrome browser plugin called MetaMask. This will allow websites (that you authorize) access to your Ethereum account.
2. If you made a new account, buy some Ether. The MetaMask plugin has a button that will allow you to buy Ether from Coinbase.
3. Once you have the plugin installed, this website will recognize it and add buttons that allow you to bid on, buy and sell punks directly in the interface.
4. For example, you can buy Punk #5254 for 46.68 ETH ($146,279.24 USD).