Back in the bad old days of Linux, you could easily damage your monitor with the wrong xorg.conf settings.
Back when a certain kind of line printer was commonplace (has a circulating ribbon with the typeface repeated, and n hammers in a line going across the entire width) programmers could sabotage the printer by printing the pattern on the ribbon. This would cause all of the hammers to fire at once, which the machine wasn't designed to withstand.
I've also heard of monitors being broken by having the speaker output the resonant frequency of the glass cover. However, I can't vouch for this one.
Back when a certain kind of line printer was commonplace (has a circulating ribbon with the typeface repeated, and n hammers in a line going across the entire width) programmers could sabotage the printer by printing the pattern on the ribbon. This would cause all of the hammers to fire at once, which the machine wasn't designed to withstand.
I've also heard of monitors being broken by having the speaker output the resonant frequency of the glass cover. However, I can't vouch for this one.