1Kprojects - Neglected side projects for less than $1000.
Transferslot - Easily buy and sell side-projects
SideProjectors - Marketplace to buy and sell side projects
Flippa - Flippa is a platform for trading websites.
buysellwebsite - Created by two California attorneys, WebsiteBroker.
Ship Your Side Project - Make enormous progress on your side project in just 6 weeks