For those in or near Santo Domingo, the Museo de Arte Moderna in the national cultural complex in Gazcue has an excellent exhibit of some of the best contemporary art being created in the DR. The 24th (2007) Bienal Nacional de Artes Visuales that's being held there is definitely worth checking out.
(The photo is from the previous Bienal)
(The photo is from the previous Bienal)