Igloo is an intranet you'll actually like: built with easy-to-use, integrated apps like shared calendars, Twitter-like microblogs, file sharing, and more. Everything you need is built-in, and everything is social. This means when you upload a file or write a corporate blog post, your team can share it, comment on it, rate it, like it, and even manage versions in the same spot.
If your company has a legacy intranet built on SharePoint, you should give Igloo a try. This report from Igloo outlines the five main areas SharePoint falls short and how Igloo does it better.