I recommended Sacrifice and still do, but one word of warning, some of the story elements may offend some deeply religious folks (you play a wizard that derives their powers and units from the god they choose to serve). The Sac Doctors also "torture" killed enemy units to convert them, though one normally does not have time to hang around and watch that (and it's rather muted compared to what it could be).

All in all it's a very unique and interesting game.

Giants is also a good choice, but Delphi is wearing a rather skimpy outfit (she was intended to be topless by the devs, and you can still patch the game that way if you wish, obviously not for your LAN party).

It's pretty much down to racing or shooters. You don't have much time to learn controls at a lan party, so it should be games that are easy to play on the fly. Is Descent 3 multiplayer viable for lan? Guilty gear is probably the only fighting game in here, so that's an option as well, though I´m not sure if it's PEGI 12.