This meetup extensively covered the igraph package with talks by Florian Sobieczky and Max Leodolter.

Florian Sobieczky: igraph - Visualising Random Walks on Graphs.

The igraph package for examples from the theory of randomly generated graphs. Questions from percolation theory and random walks such as connectivity, isoperimetry, amenability and phase transitions have been discussed in the framework of the routines from igraph. Examples from social network theory, traffic networks, and production environments have been presented.

You can check out the code here.

Max Leodolter: igraph Applications for Transportation Networks

Max gave an introduction to the igraph package including real-world applications (slides follow asap).