Back in the old days, when viruses ware written in assembler, were small enough to hide in the boot sector of a floppy disk, were able to attach themselves to a file without anyone noticing (and files were quite small those days), had stealth capability, and could influence your hardware directly, bypassing the operating system.
So maybe, maybe in those days, creating viruses could be seen as an achievement, or as a sport. Now, any fool can do it. And judging by the number of viruses, a lot of them do.
1. search the web for something like "Virus Construction Tool" or "Internet Worm Generator". Download it.
2. run the program (click on its icon).
3. fill in the form. Choose interesting names.
4. check the boxes to indicate how you want this virus / worm to spread (e-mail, irc, ...)
5. choose your options for 'payload'
6. click "create virus" or "generate"
7. Save the file
8. run it to see if it works.
This should create a visual basic script that will run on Windows computers and try to use the same Outlook application files to mass-mail itself. Much like the 'I love you' virus or the 'Ana Kournikova' worm.