Whenever other projects or life do not interfere, my efforts are devoted to Conjure, a make(1) replacement written, initially, in Scheme. But, after many experiments, i'm implementing what hopefully will be a working incarnation using CLOS. Still pretty much in experimental stage, its source code lives here.
Lately, i've been busy learning more about PLT Scheme's innards. More concretely, its excellent foreign function interface and its CLOS clone, Swindle, are great fun. A result of those investigations is a little library, MzFAM, which offers file alteration monitoring for MzScheme. Currently, it uses FAM/Gamin in GNU/Linux or a pure scheme implementation in other systems. Releases are available at PLaneT, including an HTML manual. The development tree is also browsable on-line in this darcs repository.
I'm the author of GNU MDK, which stands for GNU MIX Development Kit. It is an emulator of Don Knuth's MIX mythical computer, together with a MIXAL (MIX Assembly Language) compiler that produces assembly object files executable by the companion MIX virtual machine. It also allows debugging programs through step by step execution, breakpoint setting, symbol table inspection and manipulation of the contents of MIX's components (registers, memory cells and the like).
All of this can be done via a comfortable command line interface or, if you really are that kind of gal or guy, a gtk+ GUI. Last but not least, the whole enchilada is controllable, extensible and what not using the most beautiful programming language ever.
MDK comes in handy for readers of The Art of Computer Programming, although you can learn MIX/MIXAL directly from the MDK manual, which has been published by the GNU Press.
I maintain a blog devoted to the Emacs operating system called minor emacs wizardry. In addition, you can find my Emacs configuration files (together with other configuration bits) in this darcs repository.
The beauty of Emacs hinges on elisp, and i couldn't help surrendering to its call.
You can browse all my darcs repos for an assortment of other experiments.