Our family (with kids-6 and 8 years old) will be in Rome for a few days in June. Anybody know if there are any family beaches not too far away?

Rome or that part of Italy is not a great beach area. You could take the train south to Ostia. The train goes right to the beach. Requires a metro/train change at Piramide.

Sperlonga is 2 hours south with nice beaches.

There's a water park outside Rome. Though the website is showing dates for last summer. Apparently you can reach it by public transport.
http://www.aquapiper.it/

There a pool you can pay to use in a park near the Colosseum in Rome. English article has old prices. italian article has current prices:
http://www.eurocheapo.com/blog/rome-...colosseum.html
http://www.allombradelcolosseo.it/?page_id=51

Sperlonga and Gaeta to the south are great, but not exactly "nearby."

Anzio and Nettuno are only around an hour away and somewhat nicer than Lido di Ostia.

With children ages 6 & 8 I'm not sure I'd want an extended train trip just to go to the beach. The Ostia beach is easy to get to and we've been there often - You can ride the buses from the C.Colombo LIDO train stop. The further you get from Ostia (south) the nicer the beaches. So know that MOST of the beaches in this area (90%) are private and you'll have to pay to play. Many beaches in Italy operate in this manner. We always head to the public sections. Just ask and folks will direct you.

If you have a car, Fregene is close to Rome, just north of the FCO airport. The beaches are nicer there - Ostia is south of the Airport. we've also been to the beaches in the town of Fiumicino, but I would not recommend those (although one had a great outdoor bar!).

Again, if you have a car you could head to Lake Bracciano. We spent many a summer day there, with clean water (it's one of the primary water sources for the city of Rome - no motorboats allowed!), no waves, and a beach. You might look at this video for more info on Lake Bracciano:

http://tinyurl.com/lake-bracciano

Good Luck - The beach is a different experience in Italy!

Thanks, guys!!!