One of our favorite places to go in the summer is Contra Loma Regional Park Swim Lagoon. The lake's swim lagoon is like a pool except it has a sandy beach. There is an area with grass to sit and watch the kids. This year they even added some shade. The girls and I went with a group of friends and had a great time together. They played in the sand and swam for about 5 hours. What a was a fun summer day.