Frequent milestones, Code Metrics, Nightly Builds (Score 1)

Start by setting incremental project development goals and milestones such that they are less than 8 hours of work away. Every day, take 5 minutes with each developer and go over the pending milestones. If they are not making reasonable progress (more than 4 hours of work with nothing to show), then team program with them until the milestone is met. Make sure everyone is using something like CVS. Then do a clean checkout of the project code every night and:

1. Compile all code with all warnings on. - Email errors to developers.
2. Run some simple code metric scripts on all code and break it down by author or module.
3. Let the developers know you are doing this.

The code metrics are intended to show you are paying attention and to generate a bit of friendly compitition rather than to measure programmer productivity. Make an internal project development web page and post the metrics weekly.
Answer any complaints about the metrics not measuring anything useful with; "Yes I know, I'm just trying to establish some baseline statistics"