These are the artwork names and descriptions, in order of appearance:

• Aya at Yoshinogari. Yoshinogari (吉野ヶ里 遺跡, Yoshinogari iseki) is the name of a large and complex Yayoi archaeological site in Yoshinogari and Kanzaki in Saga Prefecture, Kyūshū, Japan. According to the Yayoi chronology established by pottery seriations in the 20th century, Yoshinogari dates to between the 3rd century BC and the 3rd century AD. However, recent attempts to use absolute dating methods such as AMS radiocarbon dating have shown that the earliest Yayoi component of Yoshinogari dates to before 400 BC. (Sourced from Wikipedia)
• 4chan and Sanae. Don't forget, you're here forever.
• Parsee and Friends. This was drawn for Parsee's day. Her catchphrase "Paru" has a special meaning hidden somewhere, so go find it!