Lovingly maintained by Bruce Winter and a large cadre of programmers, this is truly the kitchen sink of hobbyist home automation.
It has an active developer community and newsgroup and incorporates virtually every device which could hook up to a home automation system.
I had a few false starts getting it going. Despite an available web-based front end it's meant as a hobbyist app and not a consumer friendly front end, although with some perservance no doubt one could make it so. It's the kind of program you want to take the time to get set up properly on a dedicated (perhaps older) box, with the appropriate boot time restart scripts (I suggest Linux, of course), then leave running. Check back occasionally to the misterhouse site for bug fixes and updates, but once it's running leave it alone and enjoy.