I'm a big fan of what the 37Signals guys are doing (and yes, I love Ruby on Rails!), but it's also good to see new and interesting things being done in the project collaboration space. ProjectSpaces, from ForumOne Communications, is like Basecamp on steroids. There's a calendar, an announcements page, tools for arranging your contacts, a discussion area, a group email feature, a place to organize group tasks (and prioritize them), a document management system and a scheduler. From the site:
ProjectSpaces is a password-protected, web-based extranet tool. It provides working groups - committees, project teams, partners, members and others – with simple, powerful, secure and reliable tools for collaborating more effectively across organizational and geographic boundaries. ProjectSpaces offers powerful tools for managing multiple teams.