xlockmore-5.30 as of 22 February 2010, the maintained version of xlock

5.30
  atlantis, atunnel, biof, bubble3d, cage, fire, gears, invert, lament,
    moebius, morph3d, noof, pipes, rubik, sballs, sierpinski3d, skewb,
    sproingies, stairs, and superquadrics added to Windows version (atunnel,
    fire, lament, and sballs lack textures).
  skewb mode now scrambles, taken out of unstable category.
. Undo a cleanup in vroot.h, as xlock exits on startup with a BadWindow
    on pievwm and tvtwm.

 . from 5.29.1