this is cool, but I think this would be great to restructure. Some thoughts:
1. Allow running only one benchmark rather than all of them. Think of this as being used again and again (for example if someone is optimizing code) rather than only once.
2. Let the user specify the exact location through a URL or a directory (e.g., src/main/resources) rather than hardcoding http://snap.stanford.edu/data (you can of course mention in comments this url) or picking only from src/main/resources
3. Decompose code into components (perhaps separate classes/traits as appropriate): app code from downloading code from measuring PageRank performance from measuring Personalized pagerank performance
4. Measurement of performance should take in a parameter n that allow the benchmark to make n calls and reporting the average time. Choose a default n of 1.