Thanks for such a great question! I am sure all of the Hotdog Blog members are waiting anxiously to see if they can plan a trip to the Peanut Gallery or if it is just a fantasy place.
Good News! We can all buy tickets to a Peanut Gallery - we just have to either bring our own peanuts or bring some extra "mad money" to buy some from a vendor.
And, I might add, once again the question feeds right into my knowledge base on American culture. A home-run no matter how I look at it.
The term Peanut Gallery is American slang dating to the late 1880's referring to the balcony section of a theater--presumably from hoi polloi eating peanuts (a cheap snack) in the cheap seats. The term was popularized in the 1950s by the television show Howdy Doody, in which the host Buffalo Bob would call the child audience the peanut gallery. Whether he knew it or not, Buffalo Bob was combining two different slang traditions.
Peanut is also slang for something small or inconsequential. This use dates to the 1930s. By the early 1940's, the word was being used to mean a small or inconsequential person, or a child. This is the origin of name of Charles Schulz's comic strip.
Howdy Doody got mileage out of both senses of the term - not bad for a freckled red-head NON-DACHSIE!
It shouldn't come as a surprise that the expression Peanut Gallery came out American slang since peanuts were brought to world-wide popular culture by one America's most prolific inventors - George Washington Carver. Peanuts actually came to America by way of enslaved Africans in early Colonial America and by the mid 18th century had made it to the Master's table in the form of peanut soup.