updated 07/01/2013 AT 1:00 PM ET
•originally published 07/01/2013 AT 5:25 PM ET
In town for their son Samuel’s baptism, which took place at Garner’s family’s parish, Christ Church United Methodist, on Sunday, the pair also celebrated their eighth wedding anniversary on Saturday night.
Affleck, 40, Garner, 41, and their daughters – Violet, 7½, and Seraphina, 4 – joined Garner’s parents and her sister at an 11 a.m. service, where 16-month-old Samuel was baptized.
“He’s really cute. He was wearing little blue overalls,” a parishioner tells PEOPLE. “He kept trying to high-five the pastor as he was getting baptized.”
As for Samuel’s sisters, “Violet was very well-behaved,” the parishioner says, while “Seraphina was funny – she was running around, and Ben had to keep getting up to run after [her].”
Dressed in their Sunday best – Affleck in a fitted suit, Garner in a white dress – “they looked really happy,” the source adds.
They were in equally good spirits the night before at local pizza joint Pies & Pints, where the couple celebrated their anniversary with a low-key dinner of beer, pizza, salad – and a side of PDA.
“They were so cute, holding hands and kissing each other. She had her hand on his leg,” says fellow diner Robyn Brammer. “They were really affectionate.”
Pies & Pints owner Rob Lindeman says that the two are regulars. “Ben and Jen like to drop in when they’re in town,” says Lindeman. “They’re just really solid people. They seemed like they were having a great time.
After dinner, the pair headed to Ellen’s Homemade Ice Cream for dessert, where a source says Affleck tipped the five or six employees working at the time generously, “like $100 each.”