1. Age at which a person in the United States can drink liquor legally.
2. The day of the month when apocalypses are known to occur.
1. The 21st birthday is special. You can now enter bars and drink.
2. May 21, 2011, October 21, 2011, December 21, 2012. Need I say more?
When used referencing video games, a backlog is used to describe the pile of unplayed and/or unfinished games that a person owns.
It is another term for "stack of shame
Due to my never ending love for Skyrim, many of the games in my backlog remain untouched.