Hey guys, I posted a small tutorial on my blog about what I call Continuous Action Memory (I made that name up).
It's basically the methodology behind efficiently recording gameplay so you can watch instant replays or do other cool things. It's the same technique that is used for Starcraft replays, and a more advanced version of it was used for time manipulation in Braid. It's actually a really simple concept that can easily be applied to most games.http://www.sheftlog.com/posts/Continuous-Action-Memory.php
By the way, this is a brand new blog that I'm making from scratch, so it's still under construction, but any kind of feedback is welcome.