MagLev is Ruby that scales.
The MagLev open source project is at maglev.gemstone.com D. It includes documentation and developer notes.
You may also want to follow MagLev developers D on Twitter.
A lot of the best MagLev information is on the blog (gem)Stone Soup D by Dale Henrichs, a GemTalker. Especially check out his post, “GemStone 101: Making the Leap from RDBMS to Persistent Objects” D.
Because MagLev requires the Web Edition of GemStone/S (a.k.a GLASS), you’ll also want to see the Community for GLASS.