My favorite pastime activity for the last couple of weeks have been entering

ls -aR /

into a full screen terminal emulator and watching virtually everything in my file system ls'ed. It's hypnotizing if you stare at the screen long enough.

Of course, how long it is going to take to complete depends on how many files and directories you have and how fast your hard drive is. Another important factor is - as it is with any "dumb" process dumping stuff on screen - whether you are displaying the terminal or not. On my laptop, it takes around 1 minute to complete. You can test it with the time ls -aR / command where the time utility measures how much time a certain command takes to complete.