Why not make a 3D web browser. You wouldn't need to do the parsing, IE or something do that for you, but you could do some neat graphical effects.
Instead of tabbed viewing, have them on textured planes, or as different sides of a rotatable cube.
You could do some bump mapping where text is found to make the writing rise out of the page.
Could have a light source going around with the cursor so you don't get distracted by the slightly darker pop ups etc.
Speaking of pop-ups, they could literally pop up and off of the page and be dragged to one side.
Could ripple the plane object (mesh deformation) to show when the page is loading.
Might be pointless, but it would certainly look cool and engage the children.
Simple... yet fun!