The Chicago Cubs will attempt to do something that has only been done three times since 1985; win a best-of-seven LCS after losing the first two games.
The last team to overcome such a deficit was the 2004 Boston Red Sox, who dropped Game 3 of the ALCS at home as well before storming back to take four straight from the New York Yankees on the way to their first World Series title since 1918. They remain the only team in MLB history to overcome a 3-0 series deficit in any best-of-seven playoff round.
The other two teams to climb out of a 2-0 hole in a LCS were the 1985 St. Louis Cardinals and the 1985 Kansas City Royals. The Cardinals dropped the first two games of the 1985 NLCS in Dodger Stadium before reeling off four straight victories to advance to the World Series while the Royals lost two straight to the Blue Jays in Toronto, eventually fell behind 3-1, then battled their way off the ropes by winning three straight to clinch the ALCS. That Cardinals/Royals World Series is probably best remembered for the infamous blown call at first base by Don Denkinger that allowed the Royals to rally for a win in Game 6 before cruising in Game 7 to win the last World Series in their franchise history.
What all three of those teams have in common is the fact that they were all led by veterans. The average age of the 2004 Red Sox starters was 30.5, for the Royals it was 30.8, and for the Cardinals it was 27.25. The average age of the Cubs starters is 25, very low by comparison. The Chicago youngsters will have to show guile beyond their years if they want to avoid watching the 2015 World Series from home.