Simplify the following text for a Grade 8 native English-speaking person.
Original: The event was captured in the successful 1970 documentary movie Woodstock , an accompanying soundtrack album , and Joni Mitchell 's song `` Woodstock '' which commemorated the event and became a major hit for Crosby , Stills , Nash & Young .
Simplified: Joni Mitchell 's song `` Woodstock '' , about the event , also became a major hit song for Crosby , Stills , Nash & Young .