Hanuman is the mighty ape that helped Lord Rama fight evil forces. Hanuman is a favourite idol for lots of Hindus. People worship Hanuman because they think he has a strong body and is always helping Lord Rama.
You can read about Hanuman in the story of Ramayana. In this story Hanuman has got to find Rama's wife Sita because she has been taken away by Ravana. Ravana is the demon king of Lanka. When Hindus read the story about Hanuman they say they can learn about how to make the right choices if they are in trouble or have to do something difficult.
Some Hindus don't eat during the day – fast- on Saturdays and Tuesdays to remember to be strong and helpful like Hanuman is. When Hindus are in trouble they may say “Bajrangbali Ki Jai” — “victory to thy thunderbolt strength”.
There is a full moon in Chaitra in April and when the sun rises “Hanuman Jayanti” is celebrated as the birthday of Hanuman.
There are lots of Hanuman shrines in India.