Go to Google.com on the unsuspecting victim's computer, click on “settings” and “search settings”. There is a drop-down menu next to “interface language” where you can go nuts. Klingon is the weirdest, but how about Icelandic or Hacker?
This is one of the oldest tricks in the book, and all it requires is a little super glue and some coins. You can modernize it by gluing something that seems even more valuable like fake cell phone, then sit back and watch the frustration ensue!