Note: Most of the threads here were taken from the Ten Million 4chan Thread Archive (~95% of them), and aren't dated, don't have post numbers (except for a few times where I can make inferences), and don't have images/filenames.
IRC Threads - 2 threads - Threads directly about the IRC chat.
No.6574643 - April 9 2006 - 3 posts - Texas constitution bans atheists from public office (also first thread in the archive).
No.6574710 - April 9 2006 - 29 posts - CP/Bait on another imageboard is linked, later creating CP Sunday.
No.6574735 - April 9 2006 - 6 posts - Discussion about new "artsy" CP and Nevada-tan.
No.6574753 - April 9 2006 - 16 posts - Discussion about GETs and the 6M GET.
No.6574797 - April 9 2006 - 22 posts - Camwhore, first known instance of Xena fanfic.
No.6574804 - April 9 2006 - 6 posts - First instance of Rabbit-chan.
No.6574834 - April 9 2006 - 110 posts - Meta discussion of /b/, its memes, and bringing it back to its roots.
No.6574865 - April 9 2006 - 21 posts - FilePlanet has the O RLY Owl on the frontpage, inciting /b/ to talk about their memes real world effects.
No.6574868 - April 9 2006 - 22 posts - Discussion about if 4chan made a movie.
No.6575372 - April 9 2006 - 6 posts - "Time Traveler" has an AMA on 4chan's future. Most posts are missing.
No.6575373 - April 9 2006 - 19 posts - Anon asks for movie advice.
No.6575440 - April 9 2006 - 13 posts - Another Rabbit-chan thread.
No.6575575 - April 9 2006 - 4 posts - Guy advertises his own imageboard. Unnoteworthy except for the fact that he also advertised it on /img/ on world4ch on the same day.
No.6577797 - April 9 2006 - 6 posts - Anti-Furry Copypasta
No.6577850 - April 9 2006 - 6 posts - Relationship Advice.
No.6577858 - April 9 2006 - 40 posts - The Bush Administration was reportedly preparing to nuke Iran.
No.6578012 - April 9 2006 - 9 posts - Discussion about Scientology, /b/ decidedly against it.
No.6578052 - April 9 2006 - 24 posts - /b/ tries to find the most amount of cum ever caught on one picture.
No.6578092 - April 9 2006 - 8 posts - Rabbit-chan thread, but this time /b/ is against her.
No.6578102 - April 9 2006 - 19 posts - The Return of Magic-chan.
No.6578171 - April 9 2006 - 27 posts - Anon makes a cat fly.
No.6578323 - April 9 2006 - 6 posts - A message to all furfags.
No.6578394 - April 9 2006 - 14 posts - Discussion of forced-anon and the causes of /b/'s shittiness.
No.6578464 - April 9 2006 - 402 posts - Desu sticky. OP was later banned in the thread. Discussion amongst anons of what is to be done about Desu is also in the thread.
No.6578485 - April 9 2006 - 8 posts - Anon needs help getting around his ISP.
No.6578570 - April 9 2006 - 64 posts - /b/ shows its gay side (there was a revival of this thread an hour or so later).
No.6578582 - April 9 2006 - 11 posts - /b/ explains how everything exists from nothing.
No.6578677 - April 9 2006 - 48 posts - Ron-chan/Pete-chan makes his first appearance. Also, first thread to have a Screenshot!
No.6578825 - April 9 2006 - 28 posts - Anons computer is breaking, uses the last of his computer life to post porn.
No.6578835 - April 9 2006 - 6 posts - /b/ finds the irregularity in the paragraph.
No.6578839 - April 9 2006 - 27 posts - /b/ rates a camwhore.
No.6578845 - April 9 2006 - 21 posts - /an/-level cat thread sharing breeds.
No.6578961 - April 9 2006 - 69 posts - Originally about the Alabama Leprechaun meme, thread quickly devolves into racial arguments.
No.6579089 - April 9 2006 - 14 posts - Emergency Caturday thread called in order to counter the furry spammers.
No.6579198 - April 9 2006 - 24 posts - /b/ discusses what makes a furry.
No.6579332 - April 9 2006 - 40 posts - First instance of emo-chan.
No.6579369 - April 9 2006 - 19 posts - More semi-intelligent discussion of race, this time with genetics as reasoning.
No.6579384 - April 9 2006 - 24 posts - /b/ explains how to perform cunninlingus.
No.6579403 - April 9 2006 - 44 posts - Funny Words.
No.6579679 - April 9 2006 - 12 posts - In 1776, God created America.
No.6579683 - April 9 2006 - 55 posts - Communism vs. Nazism.