72019
In commemoration of its final month of operation , a special event was held with Christopher Lloyd and Bob Gale beginning the countdown to the ride 's closure in early August 2007 .
 Christopher Lloyd, Bob Gale
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Christopher Lloyd, Bob Gale