Yes, there is! The Anti-SOPA blackout on Wikipedia is just some JavaScript trickery that can easily be circumvented.
The easiest way to do this is to disable JavaScript in your browser. This will defeat the blackout and let you browse Wikipedia without any problems.
If you'd like to be more surgical about it, you want to block the following script from running using your favorite JavaScript or ad blocker:
http://en.wikipedia.org/w/index.php?title=Special:BannerController&cache/cn.js&303-4
I personally use the Safari extension JavaScript Blocker to manage my JavaScript blocking needs: it uses a regex-based engine. For similar tools, you'll want to use the following regex to block access to the script:
^http:\/\/en\.wikipedia\.org\/w\/index\.php\?title=Special:BannerController&cache=\/cn\.js&303-4$
Alternatively, you can use the mobile version of Wikipedia, which does not have the blackout in place.