While Mark McGwire has laid low since setting the single season home run record, Sammy Sosa's profile continues to rise. He dropped the opening puck at a Chicago- Anaheim hockey game last week, was given the key to the city in New York last week and threw out the first pitch at the World Series. But McGwire is expected to appear on the David Letterman show this week and both are expected to appear in a McDonald's ad campaign by the end of the month.