See how the 'Tropic Thunder' movie exec made the famous tighty-whities scene a reality.By Jocelyn Vena In honor of the upcoming 2010 MTV Movie Awards, Les Grossman (of "Tropic Thunder" fame) is sharing some "Great Moments in Movie History," starting with a behind-the-scenes stroke of genius on the 1983 set of "Risky Business." As we hear the intro of Bob Seger's "Old Time Rock and Roll," we're ready for a pants-less Joel Goodsen to come sliding out — only this time, he's wearing khakis.