What is Google Summer of Code?
It's an initiative by google to encourage contributions & involvement of students in open source communities. Read more about it here or there.

• SummerOfCode2015
• SummerOfCode2013
• SummerOfCode2012
• SummerOfCode2011
• SummerOfCode2009
• SummerOfCode2008
• SummerOfCode2007
• SummerOfCode2006
• GSoC Development Advices
• GSoC ApplicationTemplate
• GSoC 2015 Project Ideas
• GSoC Legacy Project Ideas
• SummerOfCode2016
• SummerOfCode Project Ideas