Clarifying house rules for Monopoly
It's important to note that there's a direct relationship between the near-ubiquitous Free Parking and no-auctions rules and people's perception that Monopoly is a game that takes forever to play.  The playing time of Monopoly is a function of how fast people run out of money, which is a function of 

a) how quickly all the properties get sold and developed and 

b) how slowly new money enters the game.  

If you don't auction properties, it takes a lot longer for all the properties to get sold.  If you put fines in Free Parking, they come back into the game.  You've now turned a 60-90 minute game into one that takes 3-4 hours to play.  The next step in this process is getting on boardgamegeek.com and telling everyone how terrible a game Monopoly is.