It's about 400 times as long as a Basketball game
In other words, 300 hours is 375 times the length of a Basketball game, and the length of a Basketball game is 0.00267 times that amount.(NBA regulation; playing time only)
Per National Basketball Association rules , a basketball game (without an overtime) consists of four periods of 0.20 hours each, for a total of 0.80 hours of playing time. The first basketball game, played in a Springfield Massachusetts YMCA, was played in 0.50 hours and ended with a score of 1-0.
It's about one-nine-hundred-fiftieth as long as Pius IX's reign
In other words, 300 hours is 0.001081 times the length of Pius IX's reign, and the length of Pius IX's reign is 925.10 times that amount.(a.k.a. Pope Blessed Pius IX, a.k.a. Giovanni Maria Mastai-Ferretti) (1792-1878)
The longest reigning Pope in the Church's history, Pius IX reigned from June 16th, 1846 to February 7th, 1878 — 277,400 hours. As the last monarchical Pope, he ruled over 3,000,000 subjects in the Papal States until 1870.
It's about 1,000 times as long as Louis-Antoine's reign
In other words, the length of Louis-Antoine's reign is 0.001 times 300 hours.(a.k.a. Louis-Antoine d'Artois, petit-fils de France, fils de France, duc d'Angoulême, a.k.a. Count of Marnes) (1830)
Following his father, Charles X's, abdication on the eve of the 1830 French Revolution, Louis-Antoine d'Artois was technically king for a period of approximately 0.30 hours on August 2nd, 1830. Louis-Antoine's only official act as king was to abdicate the throne to his nephew, the Henri, the Duke of Bordeaux.
It's about 1,500 times as long as The First spacewalk
In other words, the length of The First spacewalk is 0.00067 times 300 hours.(1965) (Alexi Lenovo, a.k.a. Алексе́й Архи́пович Лео́нов)
On March 18th, 1965, during the Voskhod 2 Soviet space mission, cosmonaut Alexey Arkhipovich Leonov conducted the first human spacewalk, which lasted 0.20 hours. The total mission length was 26 hours.
It's about one-two-thousand-five-hundredth as long as Pepi II's reign
In other words, the length of Pepi II's reign is 3,000 times 300 hours.(a.k.a. Neferkare) (2278 BCE - 2184 BCE)
The sixth dynasty pharaoh of Egypt's Old Kingdom, Pepi II Neferkare ascended to the throne at the age of six and is generally thought to have reigned until his death at the age of one-hundred — a total of 800,000 hours. His reign was the longest of any monarch in history.
It's about one-seven-thousandth as long as a Giant Tortoise's Lifespan
In other words, 300 hours is 0.00014 times the length of a Giant Tortoise's Lifespan, and the length of a Giant Tortoise's Lifespan is 7,100 times that amount.(for Adwaita, an Aldabra Giant Tortoise) (Dipsochelys dussumieri, formerly Geochelone gigantea)
Adwaita, an Aldabra Giant Tortoise who lived the later part of his life in the Alipore Zoological Gardens in Kolkata, India, was 2,200,000 hours at the time of his death. Once a pet of Major-General Robert Clive, 1st Baron Clive, who is credited with securing India as a colony of Great Britain, Adwaita lived through the entirety of India's 1,700,000 hours as a British colony.
It's about 20,000 times as long as The San Francisco earthquake of 1906
In other words, 300 hours is 20,600 times the length of The San Francisco earthquake of 1906, and the length of The San Francisco earthquake of 1906 is 0.00004850 times that amount.(1906) (Mussel Rock Fault, California) (sensible duration)
The San Francisco earthquake of 1906 caused perceptible shaking of the ground for about 0.0146 hours. The most devastating natural disaster in California's history, the quake was felt as far away and southern Oregon and western Nevada, and resulted in about 3,000 deaths, the displacement of 55% - 70% of the city's population, and the shifting of some spots of ground by up to 6 m (20 ft).