Here are the teams that OSU has no control over that could affect where the Bucks play if they win out(teams with reasonable chance of being in it at the end). And I'll put games that are possible hard games that lie ahead.
SEC-
add SEC CG
Florida-@LSU, ARK, Georg, @ So. Car, FSU(pride game)
ALA- @Ole Miss, So Car, Tenn, LSU, @ Aub
LSU- Flor, Aub, @ALA, @ Ole Miss, Ark
Aub- @ Ark, @ LSU, Ole Miss, @ Georg, ALA
Ole Miss- Ala, Ark, @ Aub, Tenn, LSU
So Car-@ ALA, @ Tenn, @ Ark, Flor, Clem
Georg is the biggest friend of OSU as stated above. The west will produce one team (likely LSU or ALA) but Ole Miss could mess that up too. A Georg win out gives them right to the East crown and knocks down Flor, Aub, and GT from messing with OSU.(not likely but the best scenario)(would produce UGA vs ALA/LSU/AUB/OLE MISS)
B12-
Add B12 CG
Tex-OKLA, @Mizz, @ Ok ST, Kan, @ A&M
OK ST-Mizz, Tex, Tex Tech, @ OKLA
Mizz-Neb, @ OK ST, Tex, Kan
Kan-OKLA, @ Tex Tech, Neb, @ Tex, Mizz
Neb-@ Mizz, Tex Tech, OKLA, @ Kan
OKLA is now OSU's friend as stated above. If they win out, that takes 4 possible teams(3 of note above) possibly out of the mix. Tex couldn't jump Okla to play in the B12 CG without 2 B12 losses from OKLA at that point. They would also produce 2 losses for OK ST, Bay, Tex A & M, and give the North winner a loss even if its Mizz or Kan. 2 loss champ wins B12. (OKLA vs Mizz/Kan/Neb)
ACC- Add ACC CG
VA Tech-BC, @ GT, UNC, @ Mary(?)
Miami-Clem, @ WF, @UNC, So Flor
GT-@ FSU, Va Tech, WF, Georg
BC-@ Va Tech, @ ND, UNC, @Mary(?)
Saying Miami does not jump OSU in either the Coaches or Harris (thanks to only a 1 point win), they could be a helper. With one Va Tech Loss, They won't jump them but can beat the likes of USF, leaving a 2 loss team to play to win the ACC. The only way Miami is back in the mix (IMO) is with 2 Va Tech ACC losses. Otherwise Va Tech plays for the ACC title.(Va Tech vs either BC/WF/Mary)
PAC 10
USC-@ ND, @ Oreg, Stan, UCLA, Ariz(?)
Oreg-@ UCLA, USC, @ Stan, @Ariz(?)
Stan-@ Ariz(?), Oreg, @ USC, Cal, ND
Oregon could be the Buckeyes best chance remaining to have USC lose, which WILL need to happen to unlock the Bucks from being tied right behind USC. Oregon is not likely to have enough in the schedule to catch the Bucks even with the USC win but a loss previous to USC wouldn't hurt. Stanford/Oregon/Arizona all control their own destiny in the PAC 10. We won't really know until the last 3 weeks of the season who is still in the hunt.
Big East
Cin-@ USF, WVU, ILL, @ Pitt
USF-Cin, @ Pitt, WVU, Miami
The Big East has a hurdle to jump to be involved. Cincy and USF play next week, If USF wins, Cincy could be done for good but USF has hard games remaining and may not have the horses to match those teams(@ Pitt, WVU, Miami). If Cincy wins, they have 3 tough games remaining that may not look good enough to voters to move them up(at least not over OSU).
BCS Busters and ND
Boise-@ Haw(?), Idaho, Nev(?)
TCU-@ Air Force, @ BYU, Utah
ND- USC, BC, Navy(
), @ Pitt, @ Stan
The Boise situation has been hashed out enough here. You can see their tough games left, but if Oreg loses again they are out for sure. TCU can be beat... the best chance is against BYU. ND has ridden the luck train all year and will lose another game, it's bound to happen.
So with OSU winning out that leaves a possible 23 teams that could reasonably affect OSU rank in one shape or form. OSU playing a ranked and undefeated Wisc next week will help OSU not get jumped with a win. We need to likely root for IOWA and PSU to win out to us(even against scUM) because that would produce the Big Ten's "Title" game involving 2 top 10 teams and Iowa would still have a shot to move back up into the top 10 after. It also shows OSU knock the pecking order off in a row(2 top 10 teams back to back). There is obviously other games that could produce upsets but I tried to avoid placing those in for a less cloudy model of what to look forward to. And always keep in mind that OSU does not have to have all the teams in front of them lose to get in. They need to get to 2 in the BCS formula. I think either a Flor or Tex loss is needed along with another USC and Va Tech loss. Other teams are likely to be taken out by natural play outs.