Summary from LocationTech & GeoPhilly present: 2015 Geo Open Source Meetup
#1 Geo tech is hard stuff
The under pinning of GEO is more than a casual hackathon learning session. There are great tools out there for making it consumable for all levels are developers, but if you want to get into the weeds prepare to wowed by a lot of very smart folks.
#2 Open Source projects abound
This was probably the tip of the iceberg regarding open source projects but all of this was covered at a high level with some showing off demos as well.
GeoGig – http://geogig.org/
GeoServer – http://geoserver.org/
WindShaft – https://github.com/CartoDB/Windshaft
Static Tiles with TileMill https://github.com/mapbox/tilemill
GeoTrellis – http://geotrellis.io/
CesiumJS – http://cesiumjs.org/
G3M – https://github.com/glob3mobile/g3m
All great but my favorite as CesiumJS, amazing what they accomplished.
#3 Philly and GEO
Definitely bigger than I thought.