Our sages teach us:
"When Adar comes in we increase our joy - When Av comes in we decrease our joy."
Hebrew: "Mshenichnas Adar Marbim b'Simcha - Mshenichnas Av M'maatim b'Simcha"
Rav Yonatan Eibeshitz z"l was known to be a wise little kid when growing up. One day upon coming home from school in the month of Adar, he decided to take out all the pots and pans from the kitchen cabinets and play some drums. His mother asked him "what is the occasion? He said "Ima, m'shenichnas Adar marbim b simcha!" (translation: "Mom, When Adar comes in we increase our joy!") He continued the party . The noise was getting a little out of hand for his mother.
Mother:"Yonatan, it's quite loud"
Yonatan: "yes Mom, when Adar comes in we increase our joy!."
By now the pots and pans were flying around the room and Yonatan was having a ball. A sudden knock at the door brought silence to the room. His mother went to answer the door and to Yonatan's surprise it was his father. Yonatan dropped his home made drums and made a run for it. He was in his bedroom within a couple seconds. After hearing what had happened, his father came to speak with Yonatan in his room.
Father: "What happened Yonatan, your mom told me that you were making alot of noise in the kitchen"
Yonatan: "Dad, but you know what our Rabbis tell us: When Adar comes in we increase our joy!"
Father: "ok, that is beautiful son... but why then did you stop when I came in?
Yonatan: "Dad, True, Mshenichnas Adar Marbim b'Simcha ... but ... Mshenichnas Av M'ma'atim b'Simcha"
(English: When Adar comes in we increase our joy... but ...when Av comes in we decrease our joy!")
Av is also the hebrew word for father - I hope you got that (-: