The Melancholy of Haruhi Suzumiya

If you have subtitles turned on, the Japanese characters, along with the English characters for the title of the episode, Endless Eight, form an infinity sign.

When the group all meets up late at night to discuss the infinite time loop they're stuck in, Mikuru is wearing two different types of shoes.

Look Closely: During the scene when Taniguchi tries to persuade Kyon and Kunikida to hit on girls with him, Haruhi and Yuki can be seen running in the background for a brief moment, already carrying their instruments. This gives a rough time frame for just when the two were asked to fill in for the missing members.

If you observe closely, when the SOS Brigade are in the Computer Club President's room, there is a poster of Aya Hirano, Yuko Goto, and Minori Chihara (Haruhi, Mikuru, and Yuki's respective seiyuus) at the side of the bed.

Explanation of Haruhi's Ribbons: (Posted since this information is not explained in the English dub.) Haruhi's colour choices come from the kanji used within the day names in Japanese.

Monday = "Moon" kanji = Yellow
Tuesday = "Fire" kanji = Red
Wednesday = "Water" kanji = Blue
Thursday = "Wood" kanji = Green
Friday = "Metal" kanji = Gold
Saturday = "Earth" kanji = Light brown
Sunday = "Sun" kanji = White

This is why Kyon comments he sort of understands what Haruhi is getting at. The numbers are Haruhi's own choice. Kyon probably comments that Monday feels more like a 1 to him because that's when the school week begins. (As a side note, North High School only has Sundays off; they attend on all Saturdays.)