Dead or Alive Xtreme: Venus Vacation is a free to play spin-off game for PC audiences in Japan. Rather than play with the girls, you play as their coach fueling them on to win volleyball matches against their peers and unlocking swimsuits and various items in the process. It’s all very Japanese and probably won’t appeal to most Western people (due to the language barrier) but is interesting to look at if you’re a fan of the Dead or Alive girls. Take a look at the Xtreme Venus Vacation gameplay and see what you’re missing.
If you think you can handle trying this out for yourselves then head on over here and follow this handy guide from Dualshockers which helps with installation and playing tips.