Assuming I've found an open source project I'm interested in, how do I evaluate the project(the members, the activity level, etc) to determine if joining the project will be a good use of my time and energy?
How to evaluate an open source project with joining in mind?
open source
Look at the source control history.From that, you can see checkins, review code, gauge the activity level, and generally see the quality of commits.  You can learn the most from just looking at the source code activity.