Sources for Data

The UCLA Dept. of Statistics Homepage: http://www.stat.ucla.edu
From the "Chance Homepage": http://www.dartmouth.edu/~chance/teaching_aids/data_sets.html
Sports Data: http://it.stlawu.edu/~rlock/sports.html
Data Resources:  http://research.ed.asu.edu/siip/webdata/
Pretty good sets of data with explanations: http://jse.stat.ncsu.edu:70/0/jse/data/

You can try journals (epidemiology journals are one good source, or if you have a subject you're interested in, try those.)
Also, talk to other professors of yours.
If you have a hobby, you might want to look for data related to that hobby.
You also might be able to use the Lesion data we'vebeen using in class.
And there are many, many other sources on the web.

A good data set should have these features:
a) You should be able to formulate a research question which the data can answer
b) You should know how the data were collected
c) You should know what the variables mean.