The crowd at Ireland’s Four Courts during a recent St. Patrick’s Day. (Dayna Smith for The Washington Post)

St. Patrick’s Day is Sunday, which means there will be a parade and plenty of celebrations throughout the region (Going Out Guide assembled a list).

It should go without saying that you should not drink and drive. But if you do celebrate on Sunday, and need a lift home, here’s a good option: SoberRide, a program that provides free cab rides to people who should not get behind the wheel.

Here’s how it works: From 4 p.m. Sunday until 4 a.m. Monday, just can call 1-800-200-TAXI (8294). If you have AT&T, just dial #WRAP on your phone. The cab fare is covered to $30, and if your fare is more than $30 you  just have to pay anything over that amount.

There are a few caveats. You have to be 21. And it’s available in the District as well as Virginia (Arlington, Fairfax, eastern Loudoun and Prince William counties and the cities of Alexandria, Falls Church, Fairfax, Manassas and Manassas Park) and Maryland (Montgomery and Prince George’s counties and the cities of Rockville, Bowie, College Park, Gaithersburg, Greenbelt and Takoma Park).

And you can’t schedule a ride in advance. We’ve heard complaints in the past from people who have tried using the service and have had to deal with long waits or interminable hold times. All we can say is that this is a free cab service being offered on St. Patrick’s Day. Of course there will be long waits and prolonged holds. Just call well in advance of when you think you may need to be picked up and be ready to wait a little while.

Also, even though cab companies in the various jurisdictions are participating, you can’t call them directly to use this program. You have to call that 1-800-200-TAXI (8294) number, and an operator will holler at the proper cab company.

In addition to St. Patrick’s Day, SoberRide is available during the holidays in December and January as well as Independence Day and Halloween.