American Football
Yes, there's an American football league in Europe, and Amsterdam has its own franchise. The Amsterdam Admirals, Amsterdam ArenA, ArenA Boulevard 73-75 (tel 020/465-4545; Metro: Strandvliet/ArenA), complete with cheerleaders, play at the Amsterdam ArenA.
Baseball
Honk if you like baseball (the game is called honkbal in Holland). The Amsterdam Pirates may not be the greatest practitioners of the art, but they have their moments, as you can see at the Sportpark Ookmeer, Herman Bondpark 5 (tel. 020/616-2151; bus: 19 or 192).
Basketball
Astronauts Amsterdam, (tel. 020/671-3910; www.astronauts.nl) play at Sporthallen Zuid, Burgerweeshuispad 54 (tel. 020/305-8305; tram: 16).
Soccer
Soccer (known as football in Europe, and voetbal in Dutch) is absolutely the biggest game in Holland. Ajax Amsterdam is invariably the best team in the land, and often is among the best in Europe. Ajax plays home matches at a fabulous modern stadium with a retractable roof, the Amsterdam ArenA, ArenA Boulevard 1, Amsterdam Zuidoost (tel. 020/311-1444; Metro: Strandvliet/ArenA). There's even an on-site Ajax Museum.