If you miss the Lunes del Cerro [1] festival, some towns and villages stage smaller Guelaguetza [1] celebrations year-round. So do a number of hotels, the most reliable of which occurs nightly at 8:30 p.m. at the Hotel Monte Albán (on Plaza Alameda de León, adjacent to the zócalo, tel. 951/516-2777, $9).
At other hotels, days may change, so call ahead to confirm: Hotel Camino Real (tel. 951/516-0611, 7 p.m. Fri., $30 show with dinner, not including drinks); Restaurant Casa de Cantera (Murguia 102, tel. 951/514-7585, 8:30 p.m., $10 per person).
Links:
[1] http://www.moon.com/destinations/oaxaca/oaxaca-city/entertainment-and-events/festivals