I found a tool called WikiMindMap
which allows you to easily browse a wiki.
I configured it for MagicPedia here: http://jpecore.heliohost.org/p2_Binary/ServerScripts/
Take a look and let me know what you think. If useful, I'll give to WebMaster Brad to see if he can host it on MagicPedia.
Type the name of a topic (that is hopefully in MagicPedia) in the box at the top and a diagram will be displayed.
*Topic groups can be opend by a click on the little plus sign in the group box.
*Clicking on the text will pop up the corresponding MagicPedia article page.
*Clicking on a green arrows (that are going around in a circle) will bring the related topic to the center and make it the main topic.
I find it a fun way to browse MagicPedia.
The server it's on is a freebie, so be patient.