DETROIT March 24: Either the Detroit Pistons or the Kansas City Kings will qualify for the playoffs in the National Basketball Association's Midwest División. The two teams square off tonight n what could be Detroit Coach Herb Brown's most important game of his short, but hectic, career. Cobo Arena, 7:30 pm, $7-$3, 962-2628. March 24: Out of the playoffs for the sixth straight season, t 's just a matter of playing out the string for our lowly Detroit Red Wings. They'll meet the struggling Washington Capitals in a National Hockey League game at Olympia. 7:30 pm, 895-7000. March 27: Bill Walton leads the Portland Trailblazers into a showdown with the Pistons at Cobo Arena (8 pm, 962-2628) while the Red Wings host the Atlanta Flames at Olympia. 7:30 pm, 895-7000. March 31 : The Chicago Bulls invade Cobo Arena for a game with the Pistons (7:30 pm, 9622628); and the Red Wings face off with the Toronto Maple Leafs at Olympia, 7:30 pm, 895-7000. April 2: Pistol Pete Maravich and the New Orleans Jazz will try to douse the Pistons' playoff hopes at Cobo Arena, 8 pm, 962-2628. April 4: Both the Philadelphia 76ers and the Detroit Pistons must win tonight if either has ideas of post-season action. Unfortunately, only one of them wilt. Cobo Arena, 7:30 pm, 962-2628. April 4: The season finalty comes to a close for the Red Wings who battle the playoff-bound Pittsburgh Penguins at Olympia, 7 pm, 8957000. April 7: The Milwaukee Bucks might clinch the Midwest División title tonight with a victory over the Pistons at Cobo Arena, 7:30 pm, 962-2628. April 9: It's the Pistons' final home game and the Atlanta Hawks provide the opposition. Cobo Arena, 7:30 pm, 962-2628. Coming April 13: The weather might not cooperate, but the Detroit Tigers are scheduled to open the home portion of their 76th Amer can League season with a single game against the Milwaukee Brewers. Tiger Stadium, 1:30 pm, $4.50-$1.50, 963-9944. ANN ARBOR March 27: The 51st annual Michigan High School Athletic Association's State Basketball Tournament concludes today with the championship games in each of four classes. Crisler Arena. HORSE RACING Thoroughbred Racing: Hazel Park, 3:30 pm Monday thru Friday, 2:30 pm, Saturday. $2.00, thru July 18. 398-1000. Harness Racing: Windsor Raceway, 8 pm, Tuesday thru Saturday, 1:30 pm, Sunday. $2.00, thru April 18. 961-9545. Harness Racing: Northville Downs, 8 pm Monday thru Saturday. $3-$2, thru April 6. 3491000. Harness Racing: Wolverine Raceway (Detroit Race Course), Coming April 12, Monday thru Saturday, 8 pm, $3-$2. 421-7170.