[rimaa]

This is going to be the most spoiler-ific thread . I agree with you that Code Geass' cliffhanger at the end of season one was one heck of a cliffhanger. In terms of animes that ended in a cliffhanger, I think Neon Genesis Evangelion comes to mind for many people but for a more recent anime Gundam 00 ended with an exciting cliffhanger that made you really want to check out season 2 when its aired. However, in terms of mid-series' cliff-hangers I liked Crest of the Stars' episode 12 when

Spoiler for what happens:

the episode ends with Jinto and Lafiel being chased in the cave, when finally there's a big explosion and viewer is led to believe that Jinto may have been seriously injured.

. Finally, many series' first episodes end with great cliffhangers to draw you into the series. Among these I liked "Shakugan no Shana" when you find out at the end of episode one that

Spoiler for what happens:

Yuji's "dead"

. I also liked "Higurashi no Naku Koro Ni" cliffhanger at the end of episode one where

Spoiler for what happens:

Kennichi thinks he found out what the villagers were hiding and Rena was walking towards him with a giant cleaver

. Gurren Laggen also had a ton of episodes that ended in cliff hangers, among these my favorite was when one of the episodes ended with

Spoiler for nia:

Nia going crazy and announcing she was part of the Anti-Spirals