Julia has greatly benefited from the Google Summer of Code. In the last 6 years, over 70+ students have contributed to Julia and various Julia packages. Many of these students have become regular Julia contributors well beyond their summer projects. Take a look at the Ideas Page and contribute your ideas.
In 2019, we received an even larger number of very high quality applications but could only fulfill 15 slots through GSoC. Not wanting to lose some very impressive students and their exciting projects, we decided to supplement the program with the Julia Season of Contributions (JSoC), using some community funds. Details on the program were announced here: https://discourse.julialang.org/t/julia-seasons-of-contributions-to-supplement-gsoc/23922
10 Julia projects were supported in GSoC 2016.
Various projects were proposed by the community in GSOC 2015. However, Julia did not make it to GSOC 2015. Julia organized its own Summer of Code this year thanks to a generous sponsorship for the same from Gordon and Betty Moore Foundation. The projects in Julia Summer of Code 2015 were.
Jacob Quinn (@quinnj), Composable streams for data transfer and processing (mentor: Viral B. Shah @ViralBShah)
Kenta Sato (@bicycle1885), Efficient data structures and algorithms for sequence analysis in BioJulia (mentor: Daniel C. Jones@dcjones)
Ambuj Agrawal, Improving debug information generation in Julia (mentor: Keno Fischer @Keno)
Julia was accepted as part of GSOC 2014. Many of the contributors in GSOC 2014 were mentors for JSOC 2015.