Haruhi, Sgt. Frog, Code Geass, Vocaloid, and Fate/Stay are the ones I can remember.
I was disappointed in the Geass reference, it's simply not as awesome as the Hayate no Gotoku episode where the Lancelot appears or the Puppeteer of Once. I'm surprised you didn't pick up on the 24 reference after Kagami's dream.
I'm actually one of the very few people that doesn't watch 24.
I don't either, but I know that sound from ... AMV Hell and the Abridged Series, I think.