Mailbox baseball

The game is destructive, of course, and juvenile as all hell, but there's no specific law against it [1], and it's not serious enough to warrant any heavy-duty police action, so the punk kids who play it tend to get away with it, especially out in the suburbs at night.
But it wouldn't bother me one tiny bit to hear that, on one of those dark and moonless nights, some homeowners were to catch up with the car full of bored, bat-wielding teenage morons and commence playing a slightly different game, namely administering some swift and well-deserved vigilante justice involving the baseball bats and the punk's prized car's (or, as often as not, the punk's parent's car's) fenders, headlights, and windshield, and perhaps also the punk's kneecaps for good measure.

18 USC § 1705 states that it is a crime to damage a mailbox or to tamper with the mail contained inside. It's federal because any mailbox is considered federal property. Other state laws may also apply; a quick Google search showed that Tennessee has a similar law, although I don't know how this would pass the double jeopardy restriction in the Constitution. Perhaps state laws were passed because the local U.S. attorneys didn't or wouldn't deal with your average suburban punk.

Source: http://www.usps.gov/postalinspectors/smashbox.htm

Author's Note: There isn't much to say here; a dictionary writeup would suffice, but "mailbox baseball" is a colloquialism not likely to be found in Webster 1913. Still, since this node lacks an actual definition of mailbox baseball, I'll take a swing at it in the interest of sociological completeness.

Mailbox baseball is a game of vandalism, somewhat widely-practiced among bored teenagers who really should not be allowed around cars. It involves a team effort: One player will drive down a residential street, fairly close to the row of curb-mounted mailboxes. A co-conspirator in the vehicle's passenger position will lean out the window with a baseball bat and attempt to club each passing mailbox. The car's speed relative to the mailbox greatly increases the effectiveness of the swing over what could be achieved by a stationary vandal, raising the possibility for the mailbox to be completely destroyed.

As noted by VT_hawkeye, this amusement is a federal crime. It's also the sort of flagrant, newsworthy delinquency that local law enforcement is highly motivated to curtail. Therefore, don't play mailbox baseball. Seriously, don't.