If you have off the wall discussions in your workspace like we do in our programmer 'corral' in the office, being one click away from an answer is a necesity. see: Pininfarina and Turpentine

To make 4 clicks now, and save more later, click on the seach engine icon (probably a big "G") in the seach input field and choose 'add engine'. you should see the link to add wikipedia (and others).

Then you can choose wikipedia from the dropdown list.