In a little under a half-hour is the last chance qualifier for the biggest spectacle in American open wheel racing. Three cars on the entry list haven’t made it into the field for the 500. Today, they have a six-hour qualifying session to run faster than at least one other car currently qualified and then try not to get bumped.

First, let’s fill you in on Indy 500 qualifying. Qualifying takes place over four days on two weekends. The first day is the run for the pole and also locks in the first 11 positions. Day two qualifies positions 12 through 22. Day three fills out the final 11 positions in the field up to the 33rd starter. Of note is that unlike almost every other motor race, Indy 500 qualifying is based on average speed over a four lap qualifying run rather than one quick lap. Also, drivers get three attempts per day per car with each driver allowed a primary and backup car.

Today is the fourth day of qualifying: Bump Day. While all 33 spots in the field have been filled out, that doesn’t mean that they’re safe. Cars not already in the field can get into the field by out-qualifying someone that is in the field. A driver that bumps into the field gets 33rd place. That driver can bump back into the field by putting in a qualifying run faster than someone else in the field. Make sense? It gives me headaches trying to figure it out, too.

As I mentioned above, there are three drivers that have yet to qualify for the 500 that are entered. Indy 500 past champion #91 Buddy Lazier, #9 Stanton Barrett, and #36 Bruno Junqueira are the three on the outside looking in. Lazier has bumped his way into the field before so he knows the pressure. Barrett is a rolling road block. He is consistently the slowest man in the Indy Car Series so his chances of racing his way in to the big race needs a lot of help from the weather and some luck to boot. Junqueira is a wild card. He hasn’t gotten any seat time in May because this ride has literally come together in the last week. His car wasn’t ready in time to qualify so he is going to have to work hard to dial that car in for a spot in the field.

And if someone gets into the field, someone has to drop out. The three cars at the back of the pack on Row 11 are in the most danger of sitting out the big race. Those three are (from fastest to slowest) #43 John Andretti, #23 Milka Duno, and #00 Nelson Philippe. Like the cars above, they have three qualifying attempts to keep themselves in the field. However, other than possibly Duno, all of the drivers in question likely have just one car so all they will get is three tries and then they’re out. The man to watch will be Philippe. His deal with the #00 car has only come together in the last week so he has very little time in this car under his belt so he has lots of room for improvement. Unlike Junqueira, though, this is Philippe’s first time in an Indy Car.

Six hours of do-or-die qualifying starts at 12 Noon Eastern on Versus… If you can find Versus.