If you go to Google today, you'll notice that its logo has been blacked out.
If you go to Wikipedia, you'll see a headline that reads "Imagine a World Without Free Knowledge," followed by the following text:
"For over a decade, we have spent millions of hours building the largest encyclopedia in human history. Right now, the U.S. Congress is considering legislation that could fatally damage the free and open Internet. For 24 hours, to raise awareness, we are blacking out Wikipedia."
The reason for these actions by Google, Wikipedia, and other major web-based companies is a pair of bills currently being considered by both houses of the U.S. Congress. They are best-known by their acronyms, SOPA and PIPA.