A few students have expressed interest in getting more details on DSP implementation and experimentation. The Spanish university project we saw during this week's lecture is very cool, and I believe there may even be a fully software implementation of it on their website.
As far as DSP authoring tools, a few of the more popular ones include:
Audiomulch
Csound
Max/MSP
Reaktor [Native Instruments]
(Many of these may have free- or shareware versions that you can try out. Also, most of these offer a lot of other cool stuff - a few are programming langues, others do granular synthesis and other fanciness, you can write entire sequenced pieces of music, etc.)
Enjoy!
-Scott