To spin up a buddies floppy drive while chatting with them, you need to Directly Connect to your buddy.  This is done by clicking on the "Connect to Send IM Image" icon in the IM window toolbar:

Once you and your buddy have established a Direct Connection, copy and paste this code to your buddy: <img src="a:">

Note: You must copy and paste this code into the IM from this webpage, typing it into the IM directly will not work.

When you paste this code into your IM you will not see anything, but when you send it, it will appear as a box with a picture of a computer in it.  Sending this code to your buddy will spin up the floppy drive, attempting to read a disk.  If there is no disk in your buddies floppy, the following dialog box will pop up:

For a longer effect, paste the code in to the IM multiple times before sending it, so it will attempt to read from the floppy more then once.