The warpig homebrew board article is a bit dated, but still completely useful in covering a on how to build a based board. It was done in the 90s, long before cheat modes and other speciality modes became commonplace.
BASIC is the most common hobbyist language. You could program a Basic Stamp without any real programming knowledge.
There is a sacrifice in speed, and funtionality, but for a typical paintball gun its MORE then required. At the other end, ASM is super fast, but can be very difficult when the programs become large, and hard to manage. "C" is the comprimise between usability, and funtionality, and is the industry standard for commercial boards.
My crappy MYSPACE
"the evidence strongly suggests that neither Billy nor Adam (Smart Parts) could have invented the electronic paintgun" -Garr M. King, U.S. Judge