unfortunately there aren't many offline multiplayer games for pc
its on pupose of course
bkz if pc had many multiplayer games many people wouldn't buy consoles
Some Fine multiplayer PC games are:
1. Blur(1-4 players split screen)
2. Fifa 07 - 12 (1-4 players same screen)
3. DiRT3 (2 players splitscreen )
4. Serious Sam 3 BFE (1-4 players splitscreen co-op)
5. Lego Batman(1-2 players co-op)
6. Lego Indiana Jones 1 and 2 (1-2 players co-op)
7. Splitsecond Velocity (1-2 players splitscreen)
8. Pes 10 - 12 (2 players or maybe more)
9. Street Fighter 4 (2 players)
10. Virtual Tennis 4 (2 players or maybe more)
11. Kane and Lynch (2 players splitscreen co-op)
12. Shadowgrounds Survivor (4 players co-op)
13. Monsters vs. Aliens (2 Players)
14. Renegade Ops (2 players splitscreen)
15. Terminator Salvation (2 players splitscreen)
16. Dynasty Warriors 6 (2 players splitscreen co-op)
17. Toy Story 3 (2 players splitscreen co-op)
18. Lego Starwars 1 - 3 (2 players co-op)
19. Lego Harry Potter year 1-4(2 players co-op)
20. Guilty Gear X2 (2 players)
21. Dungeon Defenders (1-4 Players Splitscreen co-op)
22. Little Fighter 2 (1-4 players co-op)
23. Earth Defense Force: Insect Armageddon (2 players co-op)
24.Shank 1&2
Try this to :http://www.multiplayer-an-einem-pc.blogspot.de/ (on the right sidebar, you can select english)