I have a home page at http://yi.org/rotty, where you can find personal information and my interests, as well as software projects I'm involved with. I hang out as Rotty at #scheme-on-freenode, if you want to contact me via an IM medium. You can also read my blog if you are bored.
I have started out as Guile user, because I liked its C interface (I'm interested into foreign language interfaces in general). I became developer and later maintainer of G-Wrap, which I rewrote in a more modular and object-oriented style. I also work on http://www.gnu.org/software/guile-gnome.
I recently got interested in scheme48, which is a nice and hackable implementation. Afterwards I got fortunatly made aware of Eli Barzilays paper about the foreign interface for PLT scheme by r2q2. I've (incompletely) implemented the same (or a very similiar) interface for scheme48. These and other scheme48-related FFI projects are detailed on scheme48-ffi-tng.
I also find kali-scheme-revival very interesting. I was thinking about helping out with porting Kali to scheme48 1.2, but this effort in temporarily on hold until I have less working hours (next year).
Currently, I'm working on a portability environment and library for Scheme named Spells and am thinking about setting up a planet-scheme.