If you're going to a conference, here's a leaflet you can print and give out to encourage people to contribute to MediaWiki:
http://www.mediawiki.org/wiki/File:MediaWiki_flyer_20110725-1.pdf
Also, if you'd like to teach a two-hour "How to customize/hack MediaWiki" workshop at some upcoming conference, unconference, barcamp, whatever, I can help you out. Guillaume Paumier and I are turning http://www.mediawiki.org/wiki/How_to_become_a_MediaWiki_hacker/Workshop into a syllabus that anyone can teach.
Some upcoming conferences where we could recruit more testers, users, and developers:
* Ubuntu Global Jam, 2-4 Sept., 42 events around the world https://wiki.ubuntu.com/UbuntuGlobalJam
* Open Video Conference, especially the open media developers' track, Sept. 10-12, New York City, USA http://openvideoconference.org/
* ZendCon (PHP conference), Oct. 17-20, Santa Clara, USA http://www.zendcon.com/
* PostgreSQL Europe, Oct. 18-21, Amsterdam, The Netherlands http://2011.pgconf.eu
* PHPCon Poland, Oct. 21-23, http://www.phpcon.pl/ Wikia's Łukasz Garczewski is attending and giving the talk "Do you speak English, yes I don't" and will help me out, but more help is welcome.
If you are going to one of those and you'd like Wikimedia stickers or buttons to pass out, please let me know.