NASCAR has three official series and then several other series that fall under its Home Tracks category.
The three NASCAR national series are:
-- Sprint Cup Series, which consists of 36 points races, including a 10-race playoff to crown a champion called the Chase for the NASCAR Sprint Cup.
-- XFINITY Series, which consists of 33 points races.
-- Camping World Truck Series, which consists of 22 points races.
In the pecking order, the Sprint Cup Series is the most prestigious and viewed as the major league level. The XFINITY Series is the next most prestigious and is viewed, to steal a baseball term, as the Triple-A of NASCAR. Plenty of successful Sprint Cup Series drivers like Jimmie Johnson, Matt Kenseth and Dale Earnhardt Jr. (to name a few), honed their craft on that circuit before moving up to Sprint Cup.
The Truck Series is the next level followed by the Home Tracks series, which is full of young, up-and-coming drivers looking to get to a NASCAR national series. The Home Tracks series typiclally run a limited schedule. The K&N Pro Series, especially, has been a starting ground for some notable Cup drivers such as Kevin Harvick, Joey Logano and Martin Truex Jr., to name a few.
Home Tracks consists of a group of regional stock car racing divisions that are sanctioned by NASCAR. Under this banner is:
-- K&N Pro Series East: This circuit is a stock car circuit and is run on the East coast of the United States.
-- K&N Pro Series West: This circuit is a stock car circuit and is run on the Western part of the United States.
-- Canadian Tire Series: This circuit is a stock car circuit that runs in Canada.
-- Toyota Series: This circuit is a stock car circuit that runs in Mexico.
-- Whelen Euro Series: This circuit is a stock car circuit that runs in Europe.
-- Whelen Modified Tour: This circuit mainly runs in the Northern United States and is open-wheeled stock car racing.
-- Whelen Southern Modified Tour: This circuit is the other one with open-wheeled stock car racing.
-- Whelen All-American Series: This is a points championship for NASCAR sanctioned local race tracks around the United States and Canada.
NASCAR also sanctions the NASCAR iRacing.com Series, which is an online oval racing series hosted by iRacing.com.
It is not uncommon to see a driver run in both the Sprint Cup and Nationwide Series. Several drivers do this on a routine basis when those series are at the same track. What is a bit of a rarity these days is a driver running in all three national series. Kyle Busch and Brad Keselowski will sometimes run in the three NASCAR national series events if they are at the same track.
Sprint Cup Series races are almost always the last of the three national series to run and they are typically on Sunday, but there are some Saturday night races throughout the season. XFINITY Series races are usually on Saturday, but there are some Friday night races throughout the season. The Camping World Truck Series races are typically on Friday nights, but there are some mid-week races from time to time. All three seasons start at Daytona, but there sizable gaps early in the season in the Truck Series.