Here is a simple, but fun, practical joke you can try.

Here is a simple, but fun, practical joke you can try.

You need a phone with a handset so that you can unscrew the
mouth piece and remove the pickup. It's real easy, they are just sitting
in there and not wired down. Replace the mouth piece and think up a good
excuse to get someone to use the phone. This joke was done to me when I
was in college. My roommate told me that this girl who I thought was cute
had called, and that she wanted me to call back. I felt pretty stupid yelling
into the phone trying to talk to her. And all I heard was her say 'Hello,
hello, is anyone there, hello?' After I realized what had happened, we
went out and tryed it on some other friends, with similar results.
It's a good joke because it is totally harmless, and even more
fun after a few drinks.

For a quick laugh, try:

zork | valspeak

If you don't have valspeak, I would suggest getting a copy. It's a
great way to hand in weekly reports to your boss.