Laszlo Hanyecz famously purchased two pizzas with 10,000 Bitcoin in 2010.
On May 22, 2010, Hanyecz posted on the Bitcointalk forum offering 10,000 of his mined bitcoins to anyone who would order him two pizzas. Jeremy Sturdivant, a 19-year-old in California, accepted the offer and arranged delivery of two Papa John's pizzas to Hanyecz's home. The bitcoins were worth about $41 at the time.
The transaction is remembered as the first widely known commercial purchase made with Bitcoin and is celebrated annually as Bitcoin Pizza Day. Hanyecz did not buy the pizzas directly from the restaurant with a Bitcoin payment; another person bought them with ordinary money and received the Bitcoin in exchange.
The story is often used to illustrate how dramatically Bitcoin's value changed. The 10,000 BTC would later have been worth vastly more than the pizzas, but the transaction helped demonstrate that Bitcoin could be used to exchange value for real-world goods.