When does the motorsports season begin?

Now that I've introduced myself, I figure I should probably actually talk about a motorsports topic to live up to my description.

As it stands, this is currently the 'dead time' of year... but what I'm wondering is what really signals the 'start' of the motorsports season (across series).

The Dakar Rally (now half a world away from Dakar, Morocco) started New Year's Day, but it's difficult to judge the entire motorsports domain by a single, however hard-core, race.

I used to judge the start of the season by the Daytona 500... yes, I started out as a Cup fan and branched out from there. But, because I HAVE branched out in my interests, it doesn't seem that simple now. Maybe it's just me thinking too much (get used to that).... Rally America's season starts in January (barely), as does WRC and Grand Am. NHRA gears up in February, as do the NASCAR National series. F1 and IRL start in March. And of course, every local track has its own weather-permitting schedule as well.

So, when during that six-week span does the 'season' begin? Or does it just depend on each enthusiast's own personal obsession? If that's the case.... Rolex 24 at Daytona.