Episode 4 has some blatant parodies and gags.
[spoiler]A Kanon reference?
Konata finds out what happens when you give excuses for tardiness and absences too often...
Tsukasa's hand-made cookies are a good incentive for Kona-chan to leave the house.
Beware of gifts from Konata... For Kagami and Tsukasa's birthday, Kona-chan gives respectively, the Dancho armband that Haruhi Suzumiya wears and a school uniform from
ToHeart (see Psygnius' post on the previous page), obviously for cosplay purposes. And of course, another self-referential Haruhi-related joke.
Kagami is no domestic goddess.
Konata (and by association, Aya Hirano) does a very good Crayon Shin-chan impression.
What to do during summer break? It's pretty obvious if you are Konata! COMIKET! BTW, is Tsukasa imitating Churuya-san? (Comiket? Nyoro~n

)
Flat chest FTW!
Another self-reference! Konata stays up late to watch SHnY and is on 2chan at the same time. She complains about the sequence with Nagato in SHnY ep. 9.
Konata explain to the twins how she gets her ero-games and manga -- from Dad. Doesn't mom disapprove? Well... (I would have thought that they knew about her family situation by now. /shrug)
I like LOL Fang-tan Sensei.
Hey, more self-references! Galaxy Angel on the back cover of Comptiq.
And of course appearances of Shuffle, FMP!'s Bonta-kun, Akuma from Street Fighter, Kinu Kanisawa from Tsuyokiss[/spoiler]