Short answers, pulled from the story.
On the 16th of September 1950, the Cleveland Browns and Philadelphia Eagles met for the first time ever, with 71,237 fans attending in Philadelphia. The game was billed as "The World Series of Pro Football" and the Browns, defending AAFC champions, won 35-10. A 1969 book titled The First Fifty Years listed it as one of "Ten Games That Mattered" in the league's history.
The Cleveland Browns, San Francisco 49ers, and Baltimore Colts joined the NFL intact when the All-America Football Conference folded, as announced on the 9th of December 1949. A dispersal draft on the 2nd of June 1950 divided remaining AAFC players across the 13 NFL teams.
The Los Angeles Rams were the first NFL team to have all of their games, both home and away, televised in the 1950 season. The Washington Redskins became the second team to put their full schedule on television.
Tom Fears of the Los Angeles Rams set an NFL record with 18 pass receptions in a single game against Green Bay on the 3rd of December 1950. He also led the league in receiving with 1,116 yards for the season.
At the end of the regular season, both the Cleveland Browns and New York Giants finished tied at 10-2-0 in the American Division, while the Los Angeles Rams and Chicago Bears finished tied at 9-3-0 in the National Division. The NFL had no standing procedure for this scenario, so the championship game was delayed a week to allow division tiebreaker games.
The free substitution rule was restored permanently in 1950, allowing any or all players to be replaced after any play. This change enabled teams to develop separate offensive, defensive, and special teams units.