Caleb gives good advice. what sorts of skills or interests do you have at your disposal ? This may shape your decision. What would you consider a "project" ?
If its a programming related task, one thing i like to do is trawl sourceforge or similar for projects in the "planning" stage, where you can see the project is basically dead, and take this through to a finished project.
If its a sys admin task like learning something new, you can try to deploy some real world scenarios in a visualised setup, such as load balancing or such.
Perhaps get involved with an open source project or distribution and get active in the community, you'll find people who need advice and help, some of these may have ideas for tasks.