1) The development of blockchain technology, first introduced in 2008 with the creation of Bitcoin, has enabled secure and decentralized digital transactions and led to the emergence of cryptocurrencies.

2) Usain Bolt of Jamaica holds the world records for the 100 meters and 200 meters sprints, with times of 9.58 seconds and 19.19 seconds, respectively.

3) Gelato, an Italian frozen dessert, is similar to ice cream but has a denser and creamier texture. It is made with milk, sugar, and various flavorings, such as fruit, chocolate, or nuts. Gelato is churned at a slower speed than ice cream, incorporating less air and resulting in a richer consistency. It is served at a slightly warmer temperature than ice cream, allowing the flavors to be more pronounced. Gelato is a beloved treat, particularly in Italy, where it is enjoyed in countless flavors and gelaterias.

4) George Clooney is an American actor, filmmaker, and activist. He gained fame for his role in the television series "ER" and has since starred in successful films such as the "Ocean's" trilogy, "Syriana," and "Up in the Air," winning several awards for his performances.