AlltourNative (tel. 877/437-4990, www.alltournative.com ), just south of Cancún , offers exciting Maya-theme day trips around the state of Quintana Roo. They have longstanding relationships with Maya villages near cenotes and other sites and can customize a responsible tourism plan for your travels.
Their Cobá Maya Encounter Expedition is an all-day trip that begins in Cobá  and includes a number of other local adventure activities (US$119 per person).
El Hombre Sobre La Tierra (tel. 999/927-0719, info [at] elhombresobrelatierra [dot] org, http://elhombresobrelatierra.org ) works with communities in Yucatán  and Campeche  with the broader mission of promoting environmental sustainability and food self-sufficiency, and advancing the integration of women in the economy.
These are all in play in the eco-tourism project in the village of Muchucuxcah (you can say it, it’s fun actually: “Moo-choo-KOOSH-kah”). Visiting service groups help construct an infrastructure that invites travelers to stay in their community. They call it el turismo solidario—solidarity tourism. Guests sleep in hammocks strung inside traditionally built palapas and take meals with families in the community.
For decades, the Maya Cultural Exchange (tel. 812/232-0186, www.intercambio-maya.org , US$1,095 per person per trip) has organized visits twice annually to different Maya villages, inviting doctors, nurses, dentists, pharmacists, translators, and volunteers to help run free medical/dental clinics. They also build community-directed public works projects for the village (hurricane shelters or other community buildings). Volunteers stay in the homes of Maya families.
The Moots Prehispanic Art School (tel. 984/134-7966, agusbarro [at] yahoo [dot] com [dot] ar) is run by Augustín Villalba, an Argentinian teacher who has been living in Maya villages for five years. Villalba arranges volunteer project and primitive lodging in the Tres Reyes village school; he can also help distribute any contributions.
Consider buying some pottery from the art school shop; 100 percent of the proceeds go to this important educational program. (The craft shop is to the left across from the crocodile-feeding dock, one block before the entrance to Cobá .)
Yaxunah Centro Cultural (http://yaxunahcentrocultural.org  or http://mayaresearchprogram.org ) is a small indigenous community 20 miles from Chichén Itzá  and Pisté with a unique grassroots village tourism opportunity. They welcome visitors to the community, especially volunteers who would like to share their skills with groups in the village (help document the flora of the area or teach ESL or computer classes to youth). Swim in the local cenote and tour the cultural interpretive center and gardens, or stay for a week to teach art classes, embroidery, or dance, or to plant trees.