Recently, I got bored and decided to go down the rabbit hole of defunct Bo-bobo websites (again, I should say) to see what kind of stuff I could find. During that, I stumbled across an old Livejournal fan group (which is a community blogging-type site) called "it's written as 'tears of the hair'". The archived page had posts from 2006 and 2007, and it was interesting to see people reacting to events of the manga and anime's US localization as they happened, such as a few posts talking about the Illumitoon Entertainment DVDs. However, the web capture hadn't saved much, so I decided to see if this Livejournal was even still around... And lo and behold, it was.
With the last post on the Livejournal being about Yoshio Sawai's "new" manga, Chagecha, it was almost like looking at a town's newspaper that was published right before a sudden disaster wiped the place off the face of the earth... But anyways, the site still existed in full, which was unexpected to say the least! Among the old posts, I found one from 2004 by a user named Kagenami that described a live event called BoboYa (ボボ屋, or Bobo Shop).
From July 24 to August 8, a special event store was opened in Tokyo Station's Meitengai underground shopping area. It sold various Bo-bobo related merchandise, and examples including T-shirts, pins, and the like, as well as the CD, Bobobo-bo Bo-bobo ~This is Hanage! Hajike Matsuri~ Sound Collection. In the first two days of the event's launch, some special guests made an appearance. On the first day of the event, the seiyuu of Bo-Bobo, Takehito Koyasu appeared, and on the second day, the seiyuu of Beauty, Ai Nonaka appeared. Also, On both days, the band Freenote (known for "Kirari Tune", the anime's second ending theme) played live onstage. The store also apparently held daily events after that. There are other details as well, but I think it'd be better if I just linked the live journal post: https://bobobobo-bobobo.livejournal.com/1440.html
The post is supposed to have image with it, but it seems to be broken now (likely due to the age of it. that, and livejournal has definitely undergone a format change since then). So of course, I did a Google search to see if there were any images left at all on this event. And even after checking Nico Nico Douga, this is the only one I could find:
This image was posted on a Livedoor blog (a Japanese blogging site). It too describes an account of the event, so if you can read Japanese or want to try plugging it into a translator, check it out: http://blog.livedoor.jp/womanblog/archives/5543396.html
Live events are something that tend to easily become lost media with any series, simply due to the brief and hard-to-document nature of them, so the fact even this much information still exists on this is really lucky!