For a girl: For the service, a nice top and skirt would be appropriate, and for the party, a party dress that is in style.
For a boy: For the service, wear a polo and khakis, and for the party, wear a suit and tie.
Grammatically, You say B'nai Mitzvah just as you would Bar Mitzvah or Bat Mitzvah.
Obviously, it is a difficult thing to tell someone how much money they should give as an appropriate gift for a Bar Mitzvah, since everyone's financial situation is very different and every Bar Mitzvah participant expects different levels of gratitude from different people. However, $36 is perfectly appropriate as a gift to give your classmate for his Bar Mitzvah, even though it would probably be an inappropriate amount for a close, working relative.
Beanbags chairs are a casual piece of furniture and would not be appropriate in many office settings. However, the appropriateness will depend on the atmosphere of the specific office in question. If the office has a casual attitude, then a casual piece of furniture is a perfect match!
The most appropriate would be "Mazol Tov" which means congratulations in Hebrew. Also, I should point out that the term is Bar Mitzvah or Bat Mitzvah (Bar for a boy, bat for a girl).
Yes, the boy is called 'a/the bar mitzvah' which translates as 'son of mitzvah'. For a girl, it would be 'a/the bat mitzvah' 'daughter of mitzvah'.
You would really have to discuss this with him and see what he has to say as he is the only that can answer this. But if it seems most of your time is spent in bed so to speak then I would guess a casual thing.
Letting her win would be the appropriate thing to do.
There is no "appropriate" time to ask such a question but when your having a casual conversation and she is in an ok mood would be the best in case she gets offended.
The kind of food that would be appropriate would be foods popular among Ashkenazi (Eastern European) Jews. These foods include gefilte fish, matzoh ball soup, challah, pierogies, and blintzes.
Appropriate business clothes would be clothes that are considered to be business casual. Clothes that are torn, too short, and shows too much cleavage, should not be worn in a business.
Multiples of $18 is the tradition.
A bar mitzvah is a male who is old enough to be considered an adult as far as Jewish law is concerned. The youngest person to be called an adult in the Torah was Jacob's son Levi, who was called a man at age 13 (Genesis 34:25). From this Judaism established that age as being the age of a bar mitzvah.