How much did your biggest "tech" mistake cost?

NotQuiteReal writes: What is the most expensive piece of hardware you broke (I fried a $2500 disk drive once, back when 400MB was $2500) or what software bug did you let slip that caused damage? (No comment on the details — but about $20K cost to a client.)

Did you lose your job over it?

If you worked on the Mars probe that crashed, please try not to be the First Post, that would scare off too many people!