Reproducibility Initiative (Science Exchange) — a service offering researchers who will attempt to reproduce your work. Validated studies will receive a Certificate of Reproducibility acknowledging that their results have been independently reproduced as part of the Reproducibility Initiative. Researchers have the opportunity to publish the replicated results as an independent publication in the PLOS Reproducibility Collection, and can share their data via the figshare Reproducibility Collection repository. The original study will also be acknowledged as independently reproduced if published in a supporting journal. See also writeup in Nature.
Designing Open Projects (PDF) — IBM report with very sensible advice on steps to take when creating open projects for engagement and participation. Should be recommended reading for all who hope to get others to help.