SKI Mag sends a blogger, Hillary Rosner, to do our dirty work: Get in shape for ski season. She joins a CrossFit gym, which is reputed to be the best—and most brutal—way to get strong fast. It may be painful, but the good news is that now Rosner has a backup job...as a brick layer. Or jackhammerer. Or contestant on that reality TV show where they pull trucks of cement. Here's how she pays—and dearly—for holiday excess.