Last night I watched a canned special on the History Channel called "Secrets of the Ancient World: Ancient Inventions" which ran through a half dozen or so discoveries of ancient technological apparatus and speculated on unanswered mysteries such as the construction of the pyramids and the Nazca lines.
While looking for a good link to put here, I discovered that the US Patent and Trademark Office publishes an internal newsletter called "The PTO Pulse" which is all kinds of fun to browse through. Copies going back to 1998 are on line. This issue from April of that year contains a more intelligent review of the TV special than I would have written.
Incidentally, if you want to check out the Nazca lines (the giant animal and geometric terraglyphs in Peru), I recommend you get in touch with my friend Ingrid in Lima. She wrote her thesis on responsible cultural, ecological and agricultural-based tourism in the Nazca region. I bet she could set you up with a hot-air balloon or something.