Kutt.it - Kutt.it is a free and open source URL shortener with custom domains and stats.
1TinyLink - One Tiny Link allows you to reduce long links from websites such as Facebook, Twitter, YouTube, Linkedin as well as other sites on the internet for free.
YOURLS - YOURLS is a website that contains all the tools you need to create and launch your very own URL shortener. URL shorteners like bitly or TinyURL are fine for public use, but they offer limited options in terms of URL customization.
Polr - An open source URL shortener. A great non-profit and free alternative to bit.ly, TinyURL, or goo.gl.
Akari Link Shortener - Anime-themed URL shortener.
UrlHum - The modern, privacy-aware URL shortener built with Laravel.