Classic rock is about heavy hooks, power chords, and tight harmonies, but it’s also about letting loose and enjoying the good times — and there’s no better time than Friday evening, when we pick up our paycheck, punch out of work, and enjoy a couple days of much-needed rest and relaxation.

With spring in the air and baseball season underway, the timing is perfect for today's weekend song, given its lyrical content -- as well as its longtime status as a ballpark favorite for day games on Saturdays. We're talking, of course, about Chicago's 'Saturday in the Park,' a radio-friendly celebration of the happily idle hours we get to while away on the weekend. Can you dig it? Yes, we can.

Fittingly, the Chicago member who wrote 'Saturday' -- keyboard player Robert Lamm -- was inspired to do so after enjoying an actual Saturday in the park. As Lamm's band mate, sax player Walter Parazaider, recalled to Rolling Stone, "I was rooming with him, and we were in Manhattan on the Fourth of July. Robert came back to the hotel from Central Park very excited after seeing the steel drum players, singers, dancers and jugglers. I said, 'Man, it's time to put music to this!'"

The result was something of an early commercial breakthrough for the band. Although Chicago had certainly enjoyed robust popularity over the course of their first four releases, 'Saturday in the Park' gave them their biggest hit to that point, rising to No. 3 on the Billboard charts and helping catapult the album it was drawn from, 'Chicago V,' to smash status. In fact, the LP went on to spend more than two months at the top of the charts, ending 1972 as one of the year's biggest sellers.

The album's success was no accident, although it came with a twinge of bitter irony; after three double-album sets and a sprawling live box -- all of which leaned heavily on extended instrumental workouts -- the band were at a low creative ebb, and compensated by filling 'Chicago V' with shorter, more single-ready cuts that added up to a more manageable 45-minute single LP. But while Chicago would suffer a series of personal and commercial setbacks by the end of the decade, 'Saturday in the Park' served as a prelude to several years of radio domination -- and it remains a staple on classic rock radio, thanks in large part to the enduring, near-universal appeal of lines like "I've been waiting such a long time / For Saturday."

Saturday isn't quite here yet, but nothing's stopping us from hitting 'play' on that video down there, turning up the volume, and letting the weekend start now.

Watch Chicago Perform 'Saturday in the Park' Live in 1973

More From Ultimate Classic Rock