in the last couple years, 'fsck' and variations like 'fscking' have entered the common vocabulary, particularly in an online context, as a way of swearing without really swearing. you see it all over blogs and in email. occasionally, i've heard people trying to actually pronounce it in conversations.
what interests me is that there is an increasing number of people who use the slang but who aren't hardcore unix geeks, and i wonder if any of them really have any idea where the term came from.
for those people, here's a little education: fsck is a unix tool for doing a FileSystem CHeck. in the old days, linux filesystems like ext2 were almost as poorly designed as FAT, NTFS, or HFS. if you were unlucky enough to have the power go out on you while the computer was writing data to disk, you could end up with a corrupted disk, and possibly not be able to boot off it (if the corrupted part was something necessary to the OS). if that happened, the fix was to boot off a rescue disk with a minimal kernel and run fsck to repair the disk. the process was slow and tedious and somehow always had to be done at the most inopportune times. we now have reiserfs, ext3, XFS, and other journaling filesystems that prevent this kind of tragedy from occurring.
the superficial resemblence of 'fsck' to a certain other four letter word combined with the fact that fsck was mostly used in situations of frustration where swearing was already common originated the use of 'fsck' as slang among the unix crowd.
from there i'd guess that it spread out to the non geek masses via slashdot, where it became common in the comments and sigs.