1-3 — Horse racing, Aintree Grand National, Liverpool, England.
1-4 — Speedskating, World Synchronized Skating Championships, Zagreb, Croatia.
1-4 — Auto racing, NHRA, SummitRacing.com Nationals, Las Vegas.
1-4 — Men's golf, PGA Tour, Bellsouth Classic, Duluth, Ga.
1-4 — Men's golf, European PGA, Algarve Open, TBA, Portugal.
2-4 — Women's golf, LPGA, Office Depot Championship, Tarzana, Calif.
2-4 — Diving, FINA Grand Prix, Zhuhai, China.
2-4 — Canoe-Kayak, U.S. Olympic Trials, Whitewater Slalom, Copperhill, Tenn. or South Bend, Ind.
2-4 — Men's college gymnastics, NCAA championships, Champaign, Ill.
3 — Auto racing, NASCAR Busch, O'Reilly 300, Fort Worth, Texas.
3 — Men's college basketball, NCAA Division I semifinals, San Antonio.
3 — Track and field, U.S. Olympic Trial, Women's marathon, St. Louis, Mo.
3 — Athletics, IAAF race-walking challenge, Rio Major, Portugal.
3-4 — Table Tennis, North American Olympic Doubles Trials, Atlanta.
4 — Running, Zurich (Switzerland) Marathon.
4 — Auto racing, NASCAR Nextel Cup, Samsung/RadioShack 500, Fort Worth, Texas.
4 — Auto racing, Formula One, Bahrain Grand Prix.
4 — Women's college basketball, NCAA Division I championship semifinals, New Orleans.
4 — Running, Paris Marathon.
4 — Running, Rotterdam (Netherlands), Marathon.
4 — Pro hockey, NHL regular season ends.
5 — Men's college basketball, NCAA Division I championship game, San Antonio.
5 — Major League Baseball, opening day, active rosters reduced to 25 players.
5-9 — Cycling, Vuelta Ciclista al Pais Vasco, various sites, Spain.
5-11 — Tennis, WTA Tour Bausch & Lomb Championships, Amelia Island, Fla.
5-11 — Tennis, WTA Tour Grand Prix De SAR La Princesse, Casablanca, Morocco.
6 — Women's college basketball, NCAA Division I championship game, New Orleans.
7 — Pro hockey, NHL Stanley Cup playoffs begin.
8 — Men's college ice hockey, NCAA Division I championship semifinals, Boston.
8-10 — Women's college bowling, NCAA championship, Houston.
8-11 — Men's golf, PGA Tour, Masters, Augusta, Ga.
8-18 — Sailing, Mistral World Championship, Izmir, Cesmi, Turkey.
9-10 — Wrestling, U.S. Championships, Las Vegas.
9-11 — Men's tennis, Davis Cup, world group quarterfinals, Group I, American Zone and Asia/Oceania Zone Group II second round ties; Euro/African Zone Group II, first round ties; Asia/Oceania Zone Group I, second round playoff ties; Asia/Oceania Zone and American Zone Group II playoff ties; Asia/Oceania Zone Group III, Group IV and Americas Zone Group IV, various sites.
10 — Men's college ice hockey, NCAA Division I championship game, Boston.
10 — Auto racing, Grand Am, Grand American 250, Phoenix 250.
10 — Auto racing, NASCAR Busch, Pepsi 300, Nashville, Tenn.
10-17 — Sailing, Tornado World Championship, Palma de Mallorca, Spain.
12 — Horse racing, Irish Grand National, Fairhouse, Ireland.
12-18 — Sailing, Star Spring Championship of the Western Hemisphere, New Orleans.
12-18 — Tennis, ATP-WTA Tour Estoril (Portugal) Open.
12-18 — Tennis, ATP CAM Open, Valencia, Spain.
12-18 — Tennis, ATP U.S. Men's Claycourt Championships, Houston.
12-18 — Tennis, WTA Tour The Family Circle Cup, Charleston, S.C.
14 — Pro Basketball, NBA regular season ends.
15-17 — Women's gymnastics, NCAA championships, Los Angeles.
15-17 — Women's golf, LPGA, Takefuji Classic, Las Vegas.
15-18 — Men's golf, PGA Tour, MCI Heritage, Hilton Head Island, S.C.
15-18 — Men's golf, PGA Nationwide Tour, First Tee Arkansas Classic, Hot Springs, Ark.
15-18 — Men's golf, European PGA, TBA.
15-18 — Auto racing, NHRA, O'Reilly Spring Nationals, Houston.
15-18 — Gymnastics, Men's Artistic European Championships, Ljubljana, Slovenia.
15-18 — Synchronized swimming, Olympic Qualification Tournament, Athens, Greece.
16 — Pro football, NFL signing period ends for restricted free agents.
16-18 — Men's golf, PGA Champions, Blue Angels Classic, Milton, Fla.
16-18 — Track and field, Mt. Sac Relays, Walnut, Calif.
16-18 — Auto rally, FIA, New Zealand.
17 — Pro Basketball, NBA playoffs begin.
17 — Horse racing, Scottish Grand National, Ayr, Scotland.
17 — Auto racing, NASCAR Trucks, Martinsville (Va.) 250.
17 — Auto racing, IRL, Indy Japan 300, Motegi.
17-25 — Curling, World Championships, Gavle, Sweden.
18 — Running, Lisbon (Portugal) Marathon.
19-25 — Tennis, ATP Tennis Masters-Monte Carlo.
19-25 — Tennis, ITF Fed Cup, first round, various sites.
18 — Auto racing, NASCAR Nextel Cup, Advance Auto Parts 500, Martinsville, Va.
18 — Motorcycle racing, FIM, South African Grand Prix, Welkom.
18 — Motorcycle racing, World Superbike, San Marino, Italy.
18 — Running, London Marathon.
18 — Running, Turin (Italy) Marathon.
18 — Auto racing, CART event, Long Beach, Calif.
19 — Running, Boston Marathon.
20-May 1 — Shooting, ISSF World Cup (all events) and Olympic test event, Athens, Greece.
22-24 — Track and field, Penn Relays, Philadelphia.
22-24 — Track and field, Drake Relays, Des Moines, Iowa.
22-25 — Men's golf, PGA Nationwide Tour, Rheem Classic, Fort Smith, Ark.
22-25 — Men's golf, European PGA, Canarias Open, TBA, Spain.
22-25 — Equestrian, U.S. Olympic Eventing selection trials (Primary), Lexington, Ky.
22-25 — Men's golf, PGA Tour, Shell Houston Open.
23 — Pro football, NFL deadline for old club to exercise right of first refusal to restricted free agents.
23-25 — Men's golf, PGA Champions, Liberty Mutual Legends of Golf, Savannah, Ga.
23-May 1 — Sailing, Star World Championship, Gaeta, Italy.
24 — Auto racing, NASCAR Busch, Aaron'S 312, Talladega, Ala.
24 — Track and field, IAAF Grand Prix II, Meeting du Conseil General, Fort de France, France.
24 — Horse racing, Gold Cup, Sandown, England.
24-25 — Women's tennis, Fed Cup, World Group, first round, various sites.
24-25 — Pro football, NFL Draft, New York.
24-May 9 — Men's ice hockey, World Championships, Prague/Ostrava, Czech Republic.
25 — Auto racing, NASCAR Nextel Cup, Aaron's 499, Talladega, Ala.
25 — Running, Madrid Marathon, Spain.
25 — Auto racing, Formula One, San Marino Grand Prix, Imola.
26-May 2 — Tennis, ATP Open Seat Godo, Barcelona, Spain.
26-May 2 — Tennis, ATP BMW Open, Munich, Germany.
26-May 2 — Tennis, WTA Tour Tippmix Budapest Grand Prix, Budapest, Hungary.
26-May 2 — Tennis, WTA Tour J&S Cup, Warsaw, Poland.
27-May 2 — Cycling, Tour de Romandie, various sites, Switzerland.
28-May 1 — Synchronized swimming, U.S. Championships, Stanford, Calif.
29-May 2 — Diving, FINA Grand Prix, Victoria, B.C.
29-May 2 — Men's golf, PGA Tour, HP Classic of New Orleans.
29-May 2 — Women's golf, LPGA, Chick-fil-A Charity Championship, Stockbridge, Ga.
29-May 2 — Men's golf, PGA Nationwide Tour, BMW Charity Pro-Am at the Cliffs, Greenville, S.C.
29-May 2 — Men's golf, European PGA, Telecom Italia Open, Milan, Italy.
29-May 2 — Gymnastics, Women's Artistic European Championships, Amsterdam, Netherlands.
30-May 2 — Men's golf, PGA Champions, Bruno's Memorial Classic, Hoover, Ala.
30-May 2 — Auto racing, NHRA, Thunder Valley Nationals, Bristol, Tenn.