I reached this position when playing against ChessMaster's cyber personality Laura. The engine recommends the line starting with 25. Rg3:
[FEN ""]
[White "Bad_Bishop"]
[Black "Laura"]
[StartPly "48"]
1. d4 Nf6
2. Nf3 c5
3. d5 d6
4. c4 Qa5+
5. Bd2 Qa6
6. Qc2 Bg4
7. Nc3 Nbd7
8. e4 Bxf3
9. gxf3 h6
10. h4 e6
11. O-O-O Ne5
12. Be2 exd5
13. exd5 Be7
14. f4 Ned7
15. Rhg1 Kf8
16. Rg2 Ne8
17. h5 Bf6
18. b3 Qa3+
19. Kb1 Bxc3
20. Bxc3 Ndf6
21. Rdg1 Rg8
22. Bf3 Qa6
23. Qe2 Qb6
24. Re1 Qd8 25. Rg3 b5 26. cxb5 Nc7 27. Qd3 Rb8 28. Ba5 Qc8 29. a4 Qb7 *
To me 25. Rg3 is not intuitive and I did not consider it all in choosing a move. Granted, in the line that ChessMaster recommends, black throws away a pawn, but my question is, what is the purpose behind 25. Rg3 and why is it the best move?