Former first lady Barbara Bush celebrated her 90th birthday on Monday by spending time with her family and promoting literacy, a cause long dear to her.

Foundations set up by Bush and by Dollar General have partnered with X Prize for a competition aimed at boosting adult literacy. The $7 million competition challenges people or teams to create a mobile app capable of giving the biggest boost to adult literacy skills within 12 months.

Bush said she hopes the competition will bring “a radical breakthrough” that will help an estimated 36 million U.S. adults who read at the third-grade level or lower.

“A parent’s literacy level is a significant predictor of their child’s future educational success, influencing generations to follow,” Bush said in a statement. She created the Barbara Bush Foundation for Family Literacy more than 25 years ago while first lady; the foundation has raised $42 million since it became a public charity in 2012.

The original X Prize was awarded 11 years ago for privately funded, suborbital flight. Since then, there have been other X Prize competitions aimed at spurring innovation.

For Bush’s birthday, family members including former Florida Gov. Jeb Bush, former President George W. Bush and three other children were in Kennebunkport.

Tents were set up at St. Ann’s Church, down the street from her summer home, for a Monday evening gala featuring special guests Amy Grant, Reba McEntire and Michael W. Smith.

It was a relatively low-key day compared to last June when her husband, former President George H.W. Bush, celebrated his own 90th birthday by skydiving.

“The two of them are going to live life to the fullest. It’s not over until it’s over. I admire that about them,” said Paula Webb, a neighbor and calligrapher who posted a sign that said “Happy Birthday, Mrs. Bush” across from Walker’s Point, where generations of Bush family members have summered on Maine’s rocky coast.

Barbara Bush is known for her humor — and for speaking her mind.

“She’s a good egg, always entertaining. We like her a lot,” said Chris MacGregor, a waitress at Mabel’s Lobster Claw, where the former first lady is a fan of the peppermint stick ice cream. “She has a great sense of humor. You never know what she’s going to say.”

Bush told her granddaughter, NBC correspondent Jenna Bush Hager, in a segment on NBC’s “Today” show that she’s had a great life with her husband. “I’ve been the luckiest woman in the world, truthfully. And I know it,” she said.

She also said she’s vowed to keep quiet during the 2016 presidential race; Jeb Bush will announce his run for the Republican nomination June 15 in Miami. But she couldn’t resist adding: “I think he’s brilliant.”