We’ve all heard of cattle roundups, gang...

We’ve all heard of cattle roundups, gang roundups and even news roundups, but there’s nothing quite like that rare congregation of grills on wheels known as the “Taco Truck Roundup.”

At least six of Pasadena’s most celebrated catering trucks will go mano a mano Saturday in Central Park as part of the Cinco de Mayo festivities sponsored by El Centro de Accion Social and the city.

The trucks, which normally serve their faithful legions at street corners around town, will be judged in 12 categories, including the smoky flavor of their carne asada, the zip in their salsa and the courtesy with which they serve their wares.

Although members of the public may buy samples from the taco trucks, only the unbiased opinions of the “celebrity” judges will count when it comes to trophy time. In the interests of full disclosure, it should be noted that this reporter, ever the impartial arbiter of Mexican cooking, has been asked to keep a score card.

The free event, which runs from noon to 9 p.m. at the corner of Fair Oaks Avenue and Del Mar Boulevard, will also feature mariachis, a folkloric ballet, the vocals of Margarita Luna, the rhythms of Conjunto Jicamo and a $3.50 barbecue dinner.

But save room for the tacos, and judge for yourself.