What are some of the interesting rules of cricket that fans don’t know?

Cricket is a game which has evolved over time and has encompassed various changes in its rules and regulations. Even though cricket lovers know almost about all the laws and rules in spite of the constant change of rules and regulations there are a few rules which not even the most ardent cricket lovers will know about. Even those fans who suffer from cricket fever will not have heard of some of these rules some of which are quite absurd and leave cricket fans scratching their head. 

• LBW is not just Leg Before Wicket but Anything Before Wicket. Anything here means anything as long as the impact of the ball is within the criteria of an LBW. One does not need to look too far for an occurrence of this law on the cricket field with Sachin Tendulkar’s infamous LBW by Glen McGrath which brought this law in front of cricket fans. 
• In case the next batsman after a dismissal of the batsman before him does not come onto the field within 3 minutes or 180 seconds can be declared ‘retired hurt’ by the umpire. Even though there are special exemptions with regards to a hat-trick ball, batsmen always try to keep within the time limit. 
• Everyone who watches IPL must have seen it on the cricket field last year when R. Ashwin infamously ‘Mankaded’ Jos Butler during the KXIP and Rajasthan Royals match. In Mankad if the non-striker is outside the crease and the bowler in his follow through whips the bails off, the batsman will be declared out. Even though this dismissal falls within the laws of the game yet it has always sparked the debate that whether this dismissal falls within the spirit of the game. 
• Whenever fast bowlers are bowling, you see that their helmets are placed behind them on the ground. Seems harmless enough, but if the batsman hits the ball and the ball hits the helmet, five penalty runs are added to the score. 
• Even if the batsman has edged the ball or is clearly LBW, if the bowling team doesn’t appeal the umpire will not give it out. It is compulsory for the bowling team to appeal if they feel the batsman is out. Also if the batsman has been given out but the bowling team feels that the batsman has been unfairly given out, they can call back the batsman. The example that comes to mind is of our Captain Cool, MS Dhoni calling back Ian Bell.