Windows vs. Linux

"format c:" vs. "rm -fR /"
Technically speaking they don't do the same thing =). But both share the same humor in the tech community. While an rm -fR deletes all files from your directory (provided you have privileges), format actually writes the file allocation tables. Someone actually was having just too much time to try both.
Check it out here
PS : In case you were wondering what the technical equivalents are,
"format c:" vs. "mkfs /dev/hdaN"
"del /F /S /Q /" vs. "rm -fR /"