Simplify the following text for a Grade 13 native English-speaking person.
Original: Tournaments were played at the 1900 and 1904 games and the Intercalated Games of 1906 , but these were contested by various clubs and scratch teams , and although the IOC considers the 1900 and 1904 tournaments to be official Olympic events , they are not recognized by FIFA ; neither recognizes the Intercalated Games today .
Simplified: Demonstration tournaments were played at the 1900 and 1904 games and the `` Intercalated Games '' of 1906 , but these were contested by various clubs and scratch teams , and are not considered to be official Olympic events .