Wikipedia is not completely blacked out. From their “learn more” page:
Is it still possible to access Wikipedia in any way?
Yes. During the blackout, Wikipedia is accessible on mobile devices and smart phones. You can also view Wikipedia normally by disabling JavaScript in your browser, as explained on this Technical FAQ page. Our purpose here isn’t to make it completely impossible for people to read Wikipedia, and it’s okay for you to circumvent the blackout. We just want to make sure you see our message.
Wikipedia is not completely blacked out. From their “learn more” page:
(Admittedly, many people will not notice this.)
Finally, the day has come! My faith has been vindicated! *starts lynx*
You can also just hit Esc while the page is loading.
or append ?banner=no to the url