There are many, many Boardmaker and Boardmaker Plus activities available for free at www.adaptedlearning.com . You must have Boardmaker to use these activities.
Download Martin_Luther_King_Facts
Download Martin_Luther_King_Questions
Download MLK_Tic_Tac_Toe_Updated!
You need Boardmaker Plus for this activity - Talking BOok
Download Martin_Luther_King_Talking_Book_-_Symbolate
Here is another activity from www.adaptedlearning.com