“Tag,” a genial comedy about best buds who have been playing the same game of tag for 30 years, is about arrested adolescence at its core. And this haphazard collection of setups, stunts and gags has that same scattershot, digressive energy. The best way to appreciate this fitfully funny collection of japes and jests is to treat it like any teenage boy in your midst: Focus on the positives, and know that even its worst is only a phase.

Based on a Wall Street Journal story about 10 men who, every February, relive the tag game they started as high school students in Spokane, Wash., “Tag” whittles the group to five, who choose the merry month of May to engage in all manner of high jinks, disguises and carefully choreographed pranks to tap one another on the shoulder and announce “You’re It.” (Whoever is It at 11:59 p.m. May 31 has to live with the ignominy for a year.)

As the movie opens, Hogan (Ed Helms) goes through elaborate motions to tag Bob (Jon Hamm) and to tell him that Jerry, the only group member who’s never been tagged, is getting married later that month. Their quarry firmly in their sights, the guys – who live in various U.S. cities – join forces to descend on the wedding and finally bring the elusive Jerry to heel, even if it means sabotaging his vows.

The key to the success of “Tag” lies in the ensemble of accomplished comic players, who mesh with antic, good-natured chemistry. Helms and Hamm are joined by Jake Johnson (playing a shiftless pothead), Hannibal Buress (the master of spacey non sequiturs) and Jeremy Renner, who plays the ninjalike Jerry as if he’s auditioning for his next “Bourne” movie.

“Tag” winds up being an undemanding, if instantly disposable, pleasure. As much fun as the movie often is, an end-credit montage suggests the real-life guys probably are more amusing and ingeniously diabolical than their fictional counterparts.