PRESQUE ISLE, Maine — Birthday parties usually involve the customary things — cake, streamers, songs and games.

This weekend people in Aroostook County can enjoy all of those in two cities — without even having to bring a gift.

Today, the city of Presque Isle celebrates its 150th birthday, and on Sunday the city of Caribou kicks off its sesquicentennial celebrations.

Presque Isle’s sesquicentennial celebration has been going on all year and will continue through December, but today marks the community’s anniversary of becoming a city.

A wealth of events is in store for revelers, Theresa Fowler, executive director of the Presque Isle Chamber of Commerce, said Thursday, noting that the Presque Isle Historical Society and other organizations have events on tap.

“There are going to be competitions, games for kids and adults, carriage rides if the weather permits and birthday cake,” she said, adding that many sesquicentennial events will take place on the campus of Northern Maine Community College.

At NMCC, revelers can attend events from 11 a.m. to 2 p.m. The activities will take place in the Edmunds and Christie buildings and will include children’s activities, crafters, a County photo exhibit, entertainment, carriage rides, food vendors and the cutting of Presque Isle’s sesquicentennial birthday cake.

Anyone mailing a letter today can take the envelope to the Presque Isle post office during business hours and have their mail hand-canceled with a special sesquicentennial stamp. The stamp will bear the sesquicentennial logo, the date, city, state and ZIP code.

Historical walking tours also have started and will continue throughout the year.

Fowler said organizers were encouraging residents to come out for the event.

“It will be a great celebration,” Fowler said Thursday. “We at the Chamber feel this is something to be celebrated.”

Caribou’s festivities get under way at 2 p.m. Sunday with a Proclamation Day at the Unitarian Universalist Church marking of the official birthday of Caribou’s incorporation.

Because of limited space at the church, seating will be for 200 people with free tickets available through the Caribou Chamber of Commerce, the Caribou Public Library and the Caribou Wellness Center.

Organizers are planning events throughout the year to commemorate the city’s 150th anniversary, with the bulk of the celebration slated for two weeks Aug. 22 to Sept. 6.

Planned are a play outlining the history of the city, a time capsule, a celebration ball, parades, fireworks and athletic events.

Freelance writer Julia Bayly contributed to this report.