|How many quarterbacks can dress and or play in a single game? - Jim|
The NFL allows for a 45-man active roster, plus a 46th spot for a "3rd quarterback". That 3rd quarterback can play in the game; however, if he enters before the 4th quarter, neither of the first two QBs can re-enter the game. (If the 3rd QB enters the game in the 4th, either/both of the other two QBs can come back in.)
On the first play after the third QB enters the game, he must line up at quarterback (either under center or in shotgun). After that, he may only be used at quarterback or in kicking situations as a kicker, punter, or holder. Similarly, if the 3rd QB enters in the 4th quarter, the first two QBs can only be used as quarterbacks, kickers, punters, or holders from that point on, and the three QBs cannot under any circumstances be on the field at the same time. Violating these participation rules is an unsportsmanlike conduct penalty.
There's a history of gaming the 3rd QB rule. Most memorably, the 1999 Jets in their opening game listed backup Rick Mirer as the 3rd QB, with Vinny Testaverde and punter Tom Tupa as the first two QBs. Testaverde got hurt early, forcing the Jets to use Tupa at QB until the 4th quarter, when Mirer could come in without the Jets losing Tupa as a punter.
Similar things are happening this year with "wildcat" QBs like Pat White and Michael Vick. The Dolphins and Eagles have listed them as one of the two active QBs, leaving better-passing backup QBs Chad Henne and Kevin Kolb listed at 3QB. [Note: When Chad Pennington was hurt in the 3rd quarter of the Dolphins-Chargers game, the Dolphins put in Henne, thus removing Pennington and White from the game.]
There's nothing restricting teams from ignoring the 3rd QB rule and either putting more than 2 QBs on the 45-man active roster (thus eliminating the 46th slot) or activating only 2 QBs and not using that 46th slot for a 3rd QB (the Colts, for one, didn't have a 3rd QB last year.)
[Added 10/25/09: Roscoe Parrish, normally a WR and who has thrown 1 pass in 5 seasons, was listed at 3rd quarterback by the Bills today. He's run direct snaps occasionally, but that's a pretty weak standard to qualify at QB.]
During Stephen F. Austin's 92-0 win over Texas College, the clock kept moving in the 4th quarter regardless of play. Is there a "continuous clock" rule? - Dennis
NCAA Rule 3-2-2-a: "Any time during the game, the playing time of any remaining period or periods and the intermission between halves may be shortened by mutual agreement of the opposing head coaches and the referee."
Other NCAA games played with a continuous clock include the last 9:24 of Coastal Carolina-Savannah State in 2006 (66-6 Coastal Carolina), the 4th quarter of Oklahoma-Texas A&M in 2003 (77-0 Oklahoma after the 3rd), and the 2nd half of Notre Dame-Pittsburgh in 1968 (49-0 Notre Dame at halftime).