I use screen for various purposes. It's nice to be able to sit down at a different terminal and attach to my same session, for example. I also occasionally run some long-term commands that will blow up if my session is disconnected. The one thing I need to do with some regularity that I often forget how to do is to scroll up and see what happened a while ago.

The key is to enter copy/scrollback mode with the Ctl-a Esc command sequence.

Once in copy/scrollback mode, you can use vi-like navigation commands to move around in the scrollback buffer. This includes j and k to move one line at a time and Ctl-d and Ctl-b to move half a page at a time.

Check out the screen man page for more information.