You can spend hours on the 'Web, but are you learning anything? You are if your surf your way to HowStuffWorks. It's a big, beautiful site, and can be a little complicated, so it won't hurt to check out the tour they offer on the opening page. You can look for something specific, or just browse around their headlines of the day. News stuff. Computer stuff. Car stuff. Electronic stuff.
Since we're just starting hurricane season, let's look there. All the basic science information, in simple, easy to understand form.
For more excitement, see how different elements effect hurricane size and strength, factors like water temperature, barometric pressure and winds. You can even compare other storms from the past.
Okay, enough serious learning for now. How about some cool graphics?
Cruising around the military section I found one that explains just how a machine gun works. You click, it fires, and keeps firing.