A Data Science Central Community
Look for free online real datasets. For example you can download free datasets from the following websites.
http://www.gseacademic.harvard.edu/~willetjo/nces.htm. These datasets are already mostly cleaned up. In my view, the best way is to start from an uncleaned dataset, apply your knowledge to clean it up and making it ready in the analysis format.
You can see the book "Statistics and data analysis in Geology" by John C Davis, in that many downloadable data references are given.
SAS KNOWLEDGE BASE / SAMPLES & SAS NOTES might be helpful to you