Here's an interesting take-over effect on this Xanga blog. When you roll the mouse over one of the top menu buttons (the one with the green-yellow logo), the whole page background changes dramatically to display a "secret message".
Clicking the button whisks you to the "SubLYMONal" site, where you are asked to enter a code. When you enter the code, you are introduced to "Lymonics".
The whole thing is a promo for Sprite and is tied to The Lost Experience (see my previous post on that).