Hysterical times — that’s what grandkids provide.

Over the weekend our youngest grandson Reed made double digits. Hard to believe he’s now 10, and his brother Miles turned 12 on Monday.

Having their birthdays so close together gives us double the pleasure. We had some fun Friday evening when we gathered at the boys’ house, after a dinner out — joining little sister, Phoebe, and their mom and dad for a cookie cake and gift giving.

Reed attempted to blow out trick candles that wouldn’t give up the ghost, and then opted to open his presents and cards before digging into the cake.

If you’ve bought a card lately, you know they can really be off the wall. There are crazy cards that play the birthday song when you open them, and newer versions with a sensor that you blow on to get the card to sing or talk.

The card Aunt Jenny sent to Reed wasn’t nearly so high tech, but it proved to be the hit of the party for Phoebe, who’s 5.

“Whoopee! Hope your birthday’s a gas!” a crazy cartoon dog on the front of the card exclaimed.

Inside was a Whoopee Cushion that drew rave reviews from Phoebe who spent the rest of the evening insisting that each of us place the cushion under our bottoms. Belly laughs ensued as flatulent sounds abounded around the table — the majority of the merriment coming from Phoebe, which seemed so out of character for this curly-haired, princess-loving girly-girl.

She just kept going on and on with the joke, long after her brothers had moved on, bored with the vintage practical joke they’d obviously seen in action before.

Of course the Whoopee Cushion piqued the adults’ interest and cellphones called up Wikipedia, the online encyclopedia that’s become a household word. Spark was amazed, as we all were, that this ages-old practical joke could be traced back to the Roman Empire.

Bet that gimmick spiced up a few toga parties. Spark filled us in on some more Whoopee facts, and then I researched the subject when we got home.

Generations after Whoopee cushions delighted the Romans, it resurfaced in the 1920s or ’30s; sources I checked offered differing dates. The more modern version was created by the JEM Rubber Company of Toronto, Canada. The owner of that company initially contacted Samuel Sorensen Adams with the idea.

Adams, an inventor of practical jokes, owned S.S. Adams Company. Earlier, he’d had great success with sneezing powder and also is credited with inventing the Joy Buzzer, the timeless gimmick that gives hand-shakers a jolt.

When approached about producing a flatulent-sound-producing inflatable bag, Adams said he felt it would be “too indelicate,” “too vulgar.” The gentleman came to regret his discretion. Adams reportedly quipped that turning down the idea cost him $50,000.

It seems money talks. Later, Adams turned a deaf ear and made a like-product dubbing it the Razzberry Cushion, a more genteel moniker.

Whatever they’re called, the ages-old invention continues to delight, as evidenced by Phoebe’s reaction the other night. When someone at the table chimed in with the real thing, there wasn’t a dry eye in the house.

Laughter truly is the best medicine.