A beer manufacturer will again be sponsoring Merriweather Post Pavilion’s concert season this year. Depends might have been more appropriate: Virtually every noncountry act booked thus far by the Columbia, Md., shed had its best days at least two decades ago. Double bills of ancient, long-irrelevant bands are the rule, not the exception: Styx/Kansas, Chicago/Crosby, Stills, and Nash, and Emerson, Lake, and Palmer/Jethro Tull. Too old to rock and roll, for sure, but the too-young-to-die-argument isn’t as easy for Ian Anderson et al. to make these days. Some of the middle-agers, like the Moody Blues and Linda Ronstadt, will be bringing full-blown orchestras on the road (Ronstadt’s will be led by noted rocker Marvin Hamlisch). The youngest tyke to play Merriweather this summer will likely be Meat Loaf, whose “Born to Rock World Tour” will stop by in late July. The venue’s ads threateningly declare, “More Exciting Acts to Be Announced!” No wonder teen drug use is again on the rise.—Dave McKenna