So, I've authored a few Wikipedia entries, and have done large edits to some other, so usually a few times a week, I'll check the watchlist and keep an eye on things. I'll also periodically fix typos or reword things in articles if I'm reading. Usually I'll only bother for articles about old school video games, wrestling or music. I was reading the entry on amateur wrestler-turned-sports-entertainer Brock Lesna and notice some pretty poorly worded passages. A big problem with pro-wrestling entires is that they don't clearly distinguish wrestling storylines from real-world happenings and they come off a bit markish.
So, I edited a big part of the entry about his time in WWE. I try to preview before saving, but whenever I edit a lot of text, I end up making several follow-up edits. After a couple of these, I notice a missing comma, so I click "Edit" and I get a blank page. Figuring wikipedia just barfed or something, I try it again. Nothing. I had been just editing the section, so I go back and try to edit the entire article. It has been replace with this (possibly NSFW) entry. Right under my nose! So, I reverted the edit and went to the user's talk page. I then had to get searching through the Wikipedia help section to find out how to flag this guy as a vandal. Meanwhile, he reverted my reversion to his vandalized page again! Another wikipedia user (possibly someone who was watching his talk page) undid his edits.
I finally figured out a) how to put a vandal tag on his talk page (he's got a ton there already) and then b) how to inform the Wikipedia admins that he was a repeat offender and needed banning. Within a few minutes of that, I got a message that he was banned for one week and that this was the third time he'd been banned. The entire thing from start to finish was about 5 minutes. Kudos to the openness of wikipedia! Now the world can be more accurately informed about how Brock Lesnar almost broke his neck at Wrestlemania only to get buried by Stone Cold Steve Austin on his way out the door!