Lazarus. I mean, how can I skip something like a free Delphi clone when I write about IDEs and RAD tools? So here's the link, there are also OSX versions of it. And it's definitely an active development project. And hey, Pascal was my first high-level language after Basic when I started programming. Oh, and there's a pretty solid bridge to the Cocoa frameworks with Objective Pascal. Update: wow, that brings back nostalgia! Building command-line tools in Pascal! And the IDE isn't bad at all, it can do a lot!