Grab your pencils and a piece of paper. Make that a very large piece of paper, because you'll need the extra space to have enough room to keep track of all the full-time driver changes that occurred during the off-season in NASCAR's Sprint Cup Series.

Grab your pencils and a piece of paper.

Make that a very large piece of paper, because you'll need the extra space to have enough room to keep track of all the full-time driver changes that occurred during the off-season in NASCAR's Sprint Cup Series.

So here's your very own primer on who's in, who's out and what happened to these guys heading into the season-opening Daytona 500 on Feb. 17:

No. 00 Toyota (Michael Waltrip Racing)

Who's In (as well as Who's Out and Where'd He Go):

David Reutimann will drive the first five races before switching to the No. 44 Toyota to replace retiring teammate Dale Jarrett. When that occurs, ARCA runner-up Michael McDowell is expected to replace Reutimann in the No. 00, but don't be surprised to see former Chip Ganassi Racing driver David Stremme waiting in the wings, just in case.

No. 01 Chevrolet (Dale Earnhardt Inc.)

Who's In: Rookie Regan Smith (Sprint Cup Rookie of the Year candidate)

Who's Out: Legendary veteran Mark Martin.

Where'd He Go: Martin isn't going far. He's moved over to the No. 8 DEI Chevrolet, replacing Dale Earnhardt Jr. Running a similar part-time schedule to last season, Martin expects to compete in 24 races in the No. 8, while youngster Aric Almirola will drive the other 12 races.

No. 5 Chevrolet (Hendrick Motorsports)

Who's In: Casey Mears

Who's Out: Kyle Busch

Where'd He Go: Busch has moved to the No. 18 Toyota of Joe Gibbs Racing.

No. 8 Chevrolet (Dale Earnhardt Inc.)

Who's In: Mark Martin/Aric Almirola (Martin to drive on a part-time basis for 24 races, while Almirola will drive the other 12 races)

Who's Out: Dale Earnhardt Jr.

Where'd He Go: Earnhardt has moved to the No. 88 Chevrolet of Hendrick Motorsports.

No. 10 Dodge (Gillett Evernham Motorsports)

Who's In: Former open-wheel star Patrick Carpentier (Sprint Cup Rookie of the Year candidate)

Who's Out: Scott Riggs

Where'd He Go: Riggs has moved on to the No. 66 Chevrolet of CNC/Haas Racing

No. 18 Toyota (Joe Gibbs Racing)

Who's In: Kyle Busch

Who's Out: J.J. Yeley

Where'd He Go: Yeley has moved to the No. 96 Toyota of Hall of Fame Racing

No. 21 Ford (Wood Brothers Racing)

Who's In: Bill Elliott for Daytona 500 and other races to be determined; Jon Wood to drive in nine races and Australian driver Marcos Ambrose in 12 others. Veteran driver Ken Schrader may also be part of the mix.

Who's Out and Where'd He Go: Elliott drove 20 races in the No. 21 last season – probably more than he wanted to, but the team was in a bind when Jon Wood struggled to make the transition to Cup racing – and likely will have a greatly reduced schedule for 2008. It'll be a big surprise if the 52-year-old Elliott drives more than 10 races this season.

No. 27 Toyota (Bill Davis Racing) – renumbered from the No. 36 Toyota

Who's In: Former Formula One and CART standout Jacques Villeneuve, a Canadian native (Sprint Cup Rookie of the Year candidate)

Who's Out: Jeremy Mayfield

Where'd He Go: Mayfield will drive the No. 70 Chevrolet for CNC/Haas Racing.

No. 28 Ford (Yates Racing) – renumbered from the No. 88 Ford

Who's In: After being left without a ride two seasons ago, Travis Kvapil returns to the Cup level

Who's Out: Legendary veteran Ricky Rudd

Where'd He Go: Rudd retired at the end of last season after an illustrious career that spanned 32 seasons.

No. 40 Dodge (Chip Ganassi Racing)

Who's In: Reigning Indy Racing League and 2006 Indianapolis 500 champion Dario Franchitti (Sprint Cup Rookie of the Year candidate)

Who's Out: David Stremme

Where'd He Go: Stremme continues to search for a new full-time Cup ride. Until – or if – that happens, he'll be driving part-time in the Nationwide (formerly Busch) Series, sharing a ride in a Rusty Wallace-owned car with promising youngster Chase Austin.

No. 44 Toyota (Michael Waltrip Racing)

Who's In: David Reutimann (after the first five races are run)

Who's Out: Dale Jarrett

Where'd He Go: Jarrett is retiring from Cup racing after 23 seasons.

No. 66 Chevrolet (CNC/Haas Racing)

Who's In: Scott Riggs

Who's Out: Jeremy Mayfield, who replaced Jeff Green with four races left last season.

Where'd He Go: Mayfield hasn't gone far. He's merely swapped teams, moving from the No. 66 to the CNC/Haas joint-owned No. 70 Chevy.

No. 70 Chevrolet (CNC/Haas Racing)

Who's In: Jeremy Mayfield

Who's Out: Even though he traded rides with Scott Riggs, Mayfield technically replaces Johnny Sauter.

Where'd He Go: Sauter is driving the No. 1 Ford on the Nationwide Series and, like Stremme, Green and others, is seeking another full-time Cup ride.

No. 77 Dodge (Penske Racing)

Who's In: Former IRL and Indianapolis 500 champion Sam Hornish Jr. (Sprint Cup Rookie of the Year candidate)

Who's Out: The No. 77 car has not been active since the end of the 2005 season, last driven by Travis Kvapil.

No. 88 Chevrolet (Hendrick Motorsports) – formerly the No. 25 Chevrolet

Who's In: Dale Earnhardt Jr.

Who's Out: Casey Mears

Where'd He Go: Mears stays with Hendrick Motorsports but changes car numbers, assuming the ride in the No. 5 Chevy formerly driven by Kyle Busch.

No. 96 Toyota (Hall of Fame Racing)

Who's In: J.J. Yeley

Who's Out: Tony Raines

Where'd He Go: Raines is still searching for a new Cup ride. At this writing, he has not been able to secure a ride in either the Nationwide or Craftsman Truck Series, either.

Jerry Bonkowski is National NASCAR Columnist for Yahoo! Sports and a featured contributor for Gatehouse News Service. He can be reached at NASCARColumnist@Yahoo.com.