I'm revisiting a few things. I heard about these things a while back, but after re-watching Avi Bryant's CUSEC 2009 talk I decided to give them another whirl:
Rubinius: An alternative VM for Ruby, I'm sure most of the readers have already heard of it. Last I checked it wasn't a 1.0 release, now it is. So I'll be checking that out again.
Seaside and consequently, Smalltalk. Seaside is a web development framework written in Smalltalk which is supposedly "heretical", which is a bold enough claim to inspire interest (again). I haven't really done much with this yet, however right off the bat I am amazed by two things:
1) The installation process - there isn't really one. Grab the one-click installer here to see for yourself. There's a lot of extra junk with this installer, including the entire Pharo Smalltalk implementation and IDE (with Smalltalk there is no separation between the language and the IDE, which I find pretty cool) and the framework itself - not bad, considering it clocks in at about ~36MB. Anyway just run the executable and you're set - the zip includes the executables for Linux, Mac and Windows.
2) The speed - it takes about the same amount of time for the VM, the web server, and the entire dev environment to start up as it takes for GVim to start up. Some things inside are a bit slow like dragging windows around, but other than that it is blazingly fast. Seriously. You have to see it to believe it.
There's also some things I'm not really revisiting, but checking out for the first time. I've recently started grad studies (one of my profs was wondering last semester what the hell I was doing in another undergrad, and told me to apply for the Master's program. I got in, which is pretty cool), so I'm looking for something to write my thesis on. I know it's a bit early - I've technically only been in the program for a week - but I figure it couldn't hurt to get going on it. I'm looking at doing stuff in computational economics, and more specifically agent-based methods. Instead of the traditional approach to economics where you set up firms and individuals as rational agents that maximize some mathematical objective function, you put them into some sort of search space and they explore it in an attempt to find a better situation than the one they're currently in - although they don't necessarily have to do this, you could introduce some level of irrationality like fear of change, in which case the potential gain in utility from switching to another outcome would have to overcome some amount, but now I'm rambling and could probably continue like this all day.
Anyway if you're interested in this kind of stuff there's seems to be a bit of stuff going on at Iowa State University of all places and they have it fairly well organized. And of course there's the Santa Fe Institute which does this sort of stuff, although if you're interested in something specific you'll probably have to dig a bit.