The software is for processing a directed acyclical graph, or a DAG. Hence the name Dagobah. Dagobah is from Star Wars; it's where Yoda lives.
Lots of Star Wars references here...
The logo idea is Yoda's hands levitating some rocks in the air using the force. The force is the blue lines around the grey rocks. The rocks/force should look like a lambda symbol. Yoda's hands are green (google 'yoda hands' for plentiful examples), and could be placed anywhere in the image. Kind of like what's in the attached picture, except the 'looks like a 3 year old drew it with crayons' part.
Pigpen is a related/complimentary project, so the design should be in a similar vein: https://github.com/Netflix/PigPen . The font used there is called halogen.
Both Dagobah and PigPen are built using Clojure (http://clojure.org/), which has both a similar color scheme and the lambda integration in the logo.
I'm hoping for something visually simple, easy to get as a sticker or a shirt.