Dan Steinberg / Invision/AP 1 / 2
Dan Steinberg / Invision/AP 1 / 2

Sunday was family day for Ashlee Simpson and Pete Wentz.

The two took their son Bronx, whom they welcomed last November, to the Elizabeth Glaser Pediatric AIDS Foundation's "A Time For Heroes" celebrity carnival in L.A.

Look back at the days leading up to Ashlee Simpson's pregnancy

As Pete helped locals customize T-shirts, Ashlee stood by his side, making faces and smiling at Bronx, whom she held in her arms. One of her pals grabbed a white baby top so Pete and Ashlee could make a T-shirt for Bronx.

See how Ashlee Simpson has changed her look over the years

Pete -- who celebrated his 30th birthday Saturday at the Bank nightclub at The Bellagio Las Vegas -- also was on daddy duty at the event, holding Bronx as Ashlee chatted with some fans.

Look back at the many loves of Ashlee and Jessica Simpson

Ashlee began cracking up when a young girl approached her for an autograph and Bronx tried grabbing the girls autograph book.