Agile* is a fascinating and very modern blog that includes free geophysical phone apps for Android and very cool summary posters on geophysical topics (cheatsheets).
At the time of this blog entry cheatsheerts include Basic, Geophysics, Rock Physics, and Elastic Properties From Sonic Logs. These have to be seen to be believed, here is the Geophysics one as a tease to the rest:
I am sure the list will change over time, so you may want to checkout the Agile* download area once in a while.
Also very thoughtful is the scales of geoscience diagram:
The minds behind Agile* are Matt Hall and Evan Bianco. Great work!! In my opinion, they are the next stage of evolution in communication, organization, and sharing of geoscience knowledge.