My main project is to create a program to generate auto-routing maps for Garmin GPS receivers. See proposed project requirements. The OSM data will be translated into an intermediate format called Polish Map format for input into cGPSMapper to generate the img file that can be used in the GPSr. See my ideas for a new ruleset. I have a auto-routing version written in XSL that works for very small data sets, but XSL is the wrong tool for the job and it chokes on even moderate sized OSM files (~10MB).
I have contributed patches to Osmosis (to allow bounding box and polygon filters to return complete ways) and JOSM (to fix the autocomplete problem).
I have done a little bit of mapping (TIGER data cleanup) around Napa and Sonoma counties in California.