Along with the popular NXT-G and NXC(RobotC) programming languages there is LabView for LEGO Mindstorms (LVLM). Those who played with RoboLab in the RCX days will find it very familiar.
Rob Torok spent some time at Tufts University working with LVLM and has put together a series of great tutorials to get people up and running. For those of you possibility hitting the limits of NXT-G, LVLM is certainly a good step up in capability.
Here is the first tutorial and you can see all of them here -https://sites.google.com/site/robtorok/lvlm-tutorials/
More info about LVLM here - http://www.k12lab.com/products/NI-LabVIEW/