Blue-collar blues in a Chicago home; Weekends Like Other People Comedy by David Blomquist. Directed by Ulu Grosbard

Blue-collar blues and midlife crises fret the Chicago married couple of ''Weekends Like Other People,'' at the Marymount Manhattan Theateb. Restive warehouseman Dan (Kenneth McMillan) thinks there must be something better than the humdrum, mundane existence he shares with wife, Laurie (Rose Gregorio), and two offstage children in their modest Northwest Chicago apartment.Pragmatic Laurie, preoccupied with shopping lists and the new living-room curtains, is more inclined to take life as it comes.

Dan's hopes and dreams for better things seem to be approaching realization when his warehouse bosses notice him and mention the possibility of a move to Moline. Heavy-set Dan responds by taking up exercise and other efforts at self-improvement. But Mr. Blomquist knows better. And so does the audience. Lack of surprise is a drawback to this generally perceptive, sometimes touching comedy about the averageness of Mr. and Mrs. Average America. Dan and Laurie come through their shared crises a sadder but apparently wiser couple.

Mr. McMillan is believably comic and at times very moving as the wage earner whose gauche exterior hides a desperate inner yearning he cannot find words to express. His frustrations and inner turmoil mount as the play progresses and improves. Miss Gregorio partners him admirably as the wife who tries to cope with his clumsy ambitions until the strain becomes too great and a domestic crisis ensues. If ''Weekends Like Other People'' were somewhat more economical and somewhat less predictable, it might seem more substantial and compelling. Nevertheless, the play's honest observations of middle-American life in a plastic, TV age are well realized in the Phoenix Theater production staged by Ulu Grosbard.

Designer David Jenkins has equipped the Dan-Laurie apartment with the standard furnishings and fixtures of mass-produced anonymity.