1) In Chinese mythology, the Dragon Boat Festival (also known as Duanwu Festival) is celebrated to honor Qu Yuan, a poet and statesman of ancient China. It involves dragon boat races, eating sticky rice dumplings (zongzi), and performing rituals to ward off evil spirits and protect against diseases.

2) The word "guitar" contains three vowels: U, A, and I.

3) The first computer mouse was invented by Douglas Engelbart in 1964 and consisted of a wooden shell and two metal wheels.

4) Serena Williams is an American professional tennis player widely regarded as one of the greatest athletes in the sport. She has won numerous Grand Slam titles and Olympic gold medals and has become an influential figure both on and off the tennis court.