If you have a passion for open source and want to work on a 3-month mentored Rust project in Servo (with a stipend), consider applying!
The Rails Girls Summer of Code project ideas can be found here, and the Google Summer of Code ideas are here. Applications need not be confined to these ideas; if you have something else you want to work on let us know.
Applications for Rails Girls Summer of Code are accepted from late February to April 10th. See here for eligibility. The coding period is from July to September.
Applications for Google Summer of Code are from 14-25th March. See here for eligibility. The coding period is from 23 May to 23 August.