I came across this years ago when I watched Rhoda first run and still remember this piece of trivia today. What was Ida Morgenstern's maiden name?

I could be wrong but I seem to recall Ida's maiden name as 'Nessel' . I think it may have been stated when they discovered an old boyfriend of hers who knew her as a cheerleader in high school as well as Brenda's somewhat disastrous 40th Anniversary celebration for Martin and Ida in which was packed with Ida's relatives but only Martin's ancient mother (that even Ida called Grandma Morgenstern) was from his side (and Grandma spent the entire party holed up in in Brenda's bathroom). One of the Nessler relatives asked Brenda if she was married and when Brenda replied in the negative she sniffed that 'That's dumb!" to Brenda's cringing. Oh, and Carlton the Doorman at first claimed to have been at the party but then it turned out he was at another party with Chinese food- and only when Rhoda and Brenda pointed out that the Morgenstern parents were NOT Chinese did he realize his mistake.

You are right! Ida's maiden name was Nessel.