The hidden Google search box
It seems that Google test completely hiding the search box of the Google search results page.
A position in a Google+ community by Tom Johns spotted this first. He said he was using a beta version of Chrome, and when he did a search, the only way to submit a search query to Google was to do so in the Omnibox built into Chrome.
Here’s an image of Google’s search results page without the search box:
You can replicate it yourself by adding URL parameters to the Google search URL. For example, here’s how you can search [google] on Google without the search box.
It is believed that Google is testing this for Chrome, but I have no confirmation on this test yet.