Just For Fun / The Problem with Pen Island

If you're not careful on non-MediaWiki wikis, it's quite possible to screw yourself up via The Problem with Pen Island. Some examples from This Very Wiki:
    open/close all folders 

    A-D 

    E-K 

    L-P 

    Q-Z 


http://tvtropes.org/pmwiki/pmwiki.php/JustForFun/TheProblemWithPenIsland