I stumbled across this site today that acts as a repository for Fortran 77 subroutines that describe density functionals for use in electronic structure programs. The site is associated with the CCLRC so I assume these are the subroutines (or very close to them) that are used in GAMESS-UK.
Looking at the source code it seems that the subroutines have been generated automatically with Maple and the dfauto script that has been described in Comp. Phys. Comm. It may just be the computer/maths geek in me, but something about that seems very cool.
