"The collaborative nature of the investigation enhances all of these valuable experiences ... as well as promotes a greater appreciation for social responsibility (Scott, 1994)."

What kinds of projects can we do with our students to engage them in higher level thinking skills?

There's a resource page from Lee Summit's School District on Student Projects.

There's also, Project Based Learning, which is a learning method with a comprehensive approach to instruction. Your students participate in projects and practice an interdisciplinary array of skills from math, language arts, fine arts, geography, science, and technology.

Here's another resource for Project-Based Learning from 21st Century Schools.
Here is the approach Project Based Learning would take to adhere to its theory.