Sacco & Vanzetti
Sacco & Vanzetti are a thus unidentified musical act, listed in the names that appear on the cover of Freak Out!. They appear to be the infamous Italian-American anarchists Nicola Sacco (1891-1927) and Bartolomeo Vanzetti (1888-1927), who were convicted of murder during an armed robbery in 1920 and sentenced to execution, which was carried out in 1927. Controversy has risen over the case because evidence shows that they were unjustly tried and sentenced for a crime they didn't commit, solely because of anti-Italian prejudice and their anarchist ideology. Seeing Zappa's political interests and criticism of the American justice system this would make their inclusion in the Freak Out list understandable.
However, in the interview Fifty-Four Fab, Boss Questions ... (1966) Zappa talks about Sacco & Vanzetti in a context that seems to imply that they are some kind of musical artists:
Who are your favorites in music?
In the old days, back before Rock 'n' Roll was what was happening, I used to go for Sacco & Vanzetti. And as I grew up I found that it got harder and harder to dance to them -- when you get old coordination is more difficult. I had to switch my preference, and now all I really like is Gary Lewis and the Playboys!
In an article by F.P. Tullius in "Playboy" (1971), Zubin And The Mothers, they are mentioned again:
A critic once said that Frank's songs and his renditions of them are "conglomerates of humor, satire, chance nonfiction and the grotesque, punctuated with snorts, oinks and boings, sprinkled with bits of Motown, Sacco and Vanzetti, R&B, Rosemary De Camp and Stravinsky."