In the early 1920's helmets were leather.In the 1930's people tried to make helmets out of plastic,but they shaddered and caused worse injuries.So leather helmets survived to see another game.In the late 1960's plastic helmets were tried again and this time they suceeded.
football
It was impeccably dangerous due to the helmets inability to work up to proper standards that at which they needed to meet. Also, for other links that pertain to this question...http://alliance.ed.uiuc.edu/cdrom/hononegah/sports_folder/changes.htm http://dm12700.wordpress.com/football-in-the-1920s/(To improve the former answer, that was previously given.)
Mah Jong, crossword puzzles, football, etc. were popular games in the 1920s.
Hundreds, as college football started in the 1870s, and the NFL started in the 1920s.
boxing, baseball, football, dodgeball, basketball,
Notre Dame
Doing the harlem shake on the feild
The National Football League (NFL) was created.
Dangerous equipment and not that much padding
Knute Rockne.
Shoulder pads of the 1920s were made of leather and were somewhat heavier than the shoulder pads worn today.
Some sports that were played in the 1920s include golf, football, baseball, and boxing. Other sports were hockey, tennis, rugby, and cricket.