I made a fairly complex arena and I think some of you on the redstone board might enjoy taking a look at it.

http://www.planetminecraft.com/project/ ... a-1868372/

Some of the things it features:
-fully integrated redstone editor
-command block respawn/control system
-advanced health system

Basically it is ridiculously editable.

If you have any questions about the redstone please leave them below.