I had earlier taken an introductory class in Udacity on hadoop and map-reduce. This was conducted by cloudera and was surely interesting. Recently I landed on hortonworks website and downloaded their Hortonworks data platform (HDP) virtualbox vm. I booted this vm on my mac and got the hdp up and running. Their tutorials were really really good and I loved the UI that they have provided.
HDP's interface gives you access to the entire hadoop ecosystem. You can upload files into HDFS. Create a table and run Hive queries etc from right within the web interface provided by HDP. It was fun to playaround HDP.