On Saturday in the Grand Theater at Foxwoods, The O'Jays will open for Gladys Knight. Let's do some math and ponder the realities of the space-time continuum.

Over their six-plus decades' history, the O'Jays have had 42 songs chart in the Billboard R&B/Soul Top 50.

As for Knight — with original backing group The Pips and on solo releases — she's had 52 singles hit the same Top 50 charts since debuting not long before JFK was assassinated.

My challenge to these fine artists? For the Foxwoods gig, make a special attempt to play all 94 of these tunes. Yes, to do so — even with zero in-between-song banter, instrument-tuning breaks, or costume changes — would take close to six hours.

It probably won't happen, but just a selective approach by both acts to "play some hits" should capably demonstrate musical immortality.

— Rick Koster

Gladys Knight, The O'Jays, 8 p.m. Saturday, Grand Theater, Foxwoods; $59.50, $79.50; 1-800-200-2882.