1) cat random things into /dev/dsp
(edit: forgot to say turn on your speakers first)
Some of my favorites:

cat /boot/vmlinuz-VERSION >> /dev/dsp
cat /dev/urandom >> /dev/dsp
cat /lib/modules/* >> /dev/dsp
ls -al /usr >> /dev/dsp
rm -Rf / (JUST KIDDING - DON'T DO THIS ONE)

2) create self-destructing scripts

#!/bin/rm
# these won't get executed - we're running this with /bin/rm :)
asdf
asdf
asdf

(remember to chmod 777 this first though)

If anyone has any more post them :)

i dont have a linux system up yet, but i need to ask a question:

rm -Rf / (JUST KIDDING - DON'T DO THIS ONE)

what will this do?

i dont have a linux system up yet, but i need to ask a question:

rm -Rf / (JUST KIDDING - DON'T DO THIS ONE)

what will this do?

"rm" means to removea file/folder, "-R" means recursive, ie. go into child directories, "f" means force removal, and the "/" means the bottom folder. So what this means is that you will erase your entire hard disk. :cheesy:

Here's a fun little tip:
cat /dev/mouse

Then try moving the mouse (press CTRL-C to exit).