Don’t be surprised if you see people riding Metro on Saturday afternoon with a pillow in their hands.

A major pillow fight is going down at 2 p.m. on the grounds of the Washington Monument.

The International Pillow Fight Day event  is one of many activities in the city expected to draw crowds to the Mall this weekend.

Thousands of visitors are expected for National Cherry Blossom Festival events, and don’t forget that the Washington Nationals are hosting the Atlanta Braves at Nationals Park Saturday night.

Metro encourages riders to load their SmarTrip cards in advance.  The transit agency is taking a break from weekend track work to accommodate the visitors during the Cherry Blossom season and it is also running more eight-car trains to provide extra capacity.  Here are some tips for festival visitors.

This weekend’s fun included a zumba dance party at the Jefferson Memorial early Saturday.

On Sunday, Metro is opening rail stations at 5 a.m., two hours earlier than normal, to accommodate crowds expected for the Credit Union Cherry Blossom 10-mile run, which starts on the Washington Monument grounds at 7:20 a.m.

Stations closest to these events are Smithsonian (Blue/Orange lines), L’Enfant Plaza (Green/Yellow/Blue/Orange lines), Metro Center (Red/Blue/Orange lines) and Archives (Green/Yellow lines).

Pillow fight organizers with Capital Improv stress the importance of keeping the “prank” element of the fight alive by hiding all pillows until the fight begins.

“If you can’t hide it, come up with a clever answer as to why you’re carrying a pillow around (wanted to take a nap while ou, zumbat, it’s the chic thing to do and that’s why everyone else here is doing it, etc.),” they said.

They also ask you wait until the signal to begin, swing pillows lightly and remove glasses before the fight. It is recommended that children play outside the main pillow crowd.

“And remember… have fun!”

Check out this video from the 2012 event.