Start with a brainstorming session about what a fact is. This is an interesting activity in and of itself and will lead to serious debate. Put them into groups and have each group come up with a definition of a fact. After that, share all the facts and have a democratic vote on which definition to use; or have them debate and defend their definitions; or even let them go back to their groups and redefine their original work.
Once you have decided on a definition, give them a table with two headings; Fact, and Inference. Next, give each student an article or short reading (junior scholastic is great; http://www2.scholastic.com/browse/classmags.jsp?srcId=2, or if you have any other recommendations I would be thrilled to hear about them). While reading the article silently to themselves, students write down four to six facts that fit the definition they constructed earlier.
Switch sheets. The goal is two take a look at the facts that the other person has written and make inferences about the subject content of the article. Make some inferences, and then students write a quick summary about what they believed the article was about.
Get back with the person who summarized your article and have a chat about the actual content of the article. Come back as a class, and debrief on how easy, or difficult it was to make inferences with the information given. What would have helped you make a better inference? What kind of facts were helpful? Which were not? Why? (Do this as a class congress or perhaps a journal entry, though I prefer big group discussions for my class, it fits our environment better)