The History Project, developed by the University California, has some terrific resources on world history, many of which are engaging classroom lessons.
For example, here is a interesting lesson on genocide. It includes a graphic organizer and definitions of the eight stages of genocide. You'll also find a great lesson on the Armenian genocide with primary sources.
Studying early trade? Here's a lesson on why spices like cinnamon were so expensive and important. It includes a short PowerPoint along with a chart and primary sources.
Studying the silk road. This lesson shows students how Buddhist and Muslim art changed as it traveled along the Silk Road.
The site is worth exploring but note that some lessons are password protected.
My thanks to Angela Lee ( @) for tweeting the link.