Previous Mid-Atlantic problem sets can be practiced-with:
You can also practice with the problems from this year's North American Qualifier, at https://open.kattis.com/contests/naq17open/problems. We will also be using kattis.com for this year's Mid-Atlantic Regional contest (for the first time).
Judging solutions and data are (intentionally) non-public, but we are happy to share them with coaches; we just ask that you not publish/release it. Coaches should email email@example.com to be added to the google-group "mid-atlantic-icpc-judges-and-coaches", or for old problem set .zip's directly. (Providing a link to a faculty-page, or other evidence of coachhood, is appreciated.)
Of course, there are also oodles of contests from other regions at ICPC's on-line judge.