Well it's arguable as to whether ancient people would be able to duplicate what we invent today but who can really say given their level of intelligence and knowledge.
Our modern technology is the result of thousands of years of trial and error and knowledge accumulated over the centuries. But there are evidences that ancient man was indeed highly intelligent and skilled in ways we find hard to duplicate even today...and not just in the construction of the pyramids. Some ancient swords from India and Greece have metallurgy we cannot duplicate. There are evidences in ancient Egyptian artifacts that were core drilled at rates faster than we do so today in some of the hardest rocks on earth....they obviously had access to or developed diamond coated drills and machining techniques. There are many evidences that ancient people developed things thousands of years ago that were lost over time and had to be reinvented.
Around 2000 yeas ago, an inventor in ancient Greece named Heron invented such things as steam power, jet and rocket power, analog computers, robotics, automatons, pneumatics, syringes, coin-operated vending machines, etc... Artifacts have been found which suggest that ancient people developed optical lenses, tooth fillings and dentistry, plastic surgery, trepanation, minor brain surgery and a host of other things, Platinum and aluminum objects have been found dating to ancient times yet they are supposedly recent technologies. Some footwear found on an ancient man called Otzi the Iceman is reportedly being copied because of it's high quality in insulating properties.
"The shoes were waterproof and wide, seemingly designed for walking across the snow; they were constructed using bearskin for the soles, deer hide for top panels, and a netting made of tree bark. Soft grass went around the foot and in the shoe and functioned like warm socks. The shoes have since been reproduced by experts and found to constitute such excellent footwear that there are plans for commercial production. "
crystalinks.com/oetzi.html
Given enough time and labor and a learning process, I'm sure we could replicate the pyramids but the question still remains elusive as to how exactly they did build such things given the time period and how other cultures did as well. Some structures in South America like Puma Punku and others seem more advanced than the pyramids in some ways and also have similar construction methods in other ways...drilled holes in rocks, metal block ties or staples, etc...
Ancient knowledge and construction techniques......
http://www.ancient-wisdom.co.uk/constructiontechniques.htm
This guy knows a few things on how to move large objects and stones......
http://theforgottentechnology.com/
Optics.....
http://www.newdawnmagazine.com/Article/The_Crystal_Sun.html
http://www.answersingenesis.org/articles/2007/01/24/early-optical-technology
Dentistry....
http://news.nationalgeographic.com/news/2006/04/0405_060405_teeth_drill.html
http://news.bbc.co.uk/2/hi/science/nature/4882968.stm
Trepanation and brain surgery.......
http://www.crystalinks.com/earlymedical.html
Ancient machinery.....
"Craftsmen in ancient China were using complex machines to work jewellery long before such devices are traditionally thought to have been invented"
http://news.bbc.co.uk/2/hi/science/nature/3792819.stm
"Stone age craftsmen in China were polishing objects using diamond 2,000 years before anyone else had the same idea, new evidence suggests."
"Harvard University physicist Peter Lu and colleagues studied four ceremonial burial axes, the oldest of which dates to about 4,500 years ago. "
http://news.bbc.co.uk/2/hi/science/nature/4555235.stm
Metallurgy...platinum and aluminum objects....
http://www.ancient-wisdom.co.uk/metallurgy.htm