Do stay at Casa D'Acuna, a charming, relaxed oasis in Coban. The restaurant serves delicious grilled steaks and fish and the wine list is extensive. Rates are very reasonable.

They will arrange a tour to Semuc Champey and a tour of a local coffee finca which are both must sees. 

Do visit the artesaneal market which sets up in Central Park on Sundays.  Also visit the regular market which is located on the street behind the Cathedral.  Go inside and walk around the maze like stands, some of which sell awesome woven and embroidered huipiles and other typical clothing (often upwards of Q300-500 depending on the work and the materials).

Do the trip to Proyecto Eco-quetzal. Check out their website It includes a homestay with Maya-Q'eqchi' families. One of the few opportunities in Guatemala to really get of the beaten path!

Near Coban:  The Grotto of Chicoy is a remarkable place, often used by Mayan priests in their rituals, and well worth a visit.  Located at km 169 on the road from Guate to Coban, just north of Purulha.  You can visit it and the Quetzal Biotope (just south of Purulha) the same day. 

Chicoy Grotto (Photo: Chicoy Grotto from inside looking out)

Vivero Verapaz orchid nursery is a beautiful spot (and a nice place to lunch - there's a good restaurant).  It is particularly stunning in November-December.  It's half-an-hour's walk from the central park, or you can take a taxi for $4. 

Do visit the Calvario Church in Coban, located on a hilltop with a great view of Coban's surrounding. Also do feel free to walk in to the Catedral in the center of Coban.  The building was one of the first in this area and is hundreds of years old.  It is built like a fortress with very thick walls and includes a small chapel to the right of the main altar.  Feel free to look around when the doors are open but do be respectful.  Picture taking is usually okay but only as long as it is of the building itself.  People are another story and should be asked before taking their photo.  

Unfortunately the Parque Nacional las Victorias, which is located near el Calvario is a prime spot for muggings.  The nearby stadium is also a crime hotspot so keep away from these places unless you are with a large group or feel you have the size/ability to defend yourself from an attack (usually at knifepoint?)