If so, who was it and what was the team and year? Thanks.

Yes!
When the Eagles played the Redskins at the Vet. During the "bodybag game". Brian Mitchell came in to qb.

The Eagles used Brian Westbrook, RB at quarterback last night.

Im guessing that they have used 3 in a game but some teams have less then 3 Qbs. I think that there has never been a different player playing QB though. The game is only so long and the chances of atleast 3 QBs getting hurt is very rare.

Only in preseason my friend. These teams are Pittsburgh last year and also with Kordell back in the slash years, I think St Louis might have with Tim Couch. I have seen though one time when Denver had Jason Elam injured just to have Rouen make a fool out of himself and miss a field goal. The Broncoes had to go for 2 every time they scored.

The Chicago Bears used Walter Payton as the quarterback one game due to injuries to their playing QB's. At the time, their passing attack was terrible, and Walter was the only offensive weapon they had, so it was figured to be smarter to hike the ball to him and save one player. I remember it didn't work very well.

I believe I have seen 3 QBs used in a game, but think that is the limit. I of course am excluding the idea of "gadget" plays where a position player plays QB for ONE PLAY. They aren't playing QB when it is a one play deal.

Minnestoa Vikings used all 3 QBs this past weekend against the Bears since Johnson threw 4 interceptions, Bollinger got his shoulder Injured, and then they put in Jackson to finish the game.

No

Yes. Last year. The Jets Chad Pennington and Jay Fielder were hurt within a few plays of each other. Third stringer Brooks Bollinger came in to finish up.