Coban is not notable for what you can do here but rather what you can do from here (see "Do" section). Recall when you visit that Coban is a large city by Guatemalan standards and has levels of friendliness and prices similar to the capitol.
The most common way to get to Coban from Guatemala City is using the Monja Blanca bus service from the capital, approximately four hours. There are also competitors, as well as more expensive shuttles. A ticket to Coban on the Monja Blanca costs about 40 - 75 Quetzales per person (according to April 2015). The Monja Blanca bus station in zone 1 of Guatemala City is on the 8a avenida between the 15 and 16 calles.
Coban is a relatively walkable city in terms of size (sidewalk conditions are horrible, however, and you should always assume that cars will take the right of way). For local destinations around Coban, there are buses that leave in front of Plaza Magdalena. You can take a taxi almost anywhere around town for Q20 for something like 5 Kilometers. Always get in the taxis that are marked with a Taxi number on the door, the unmarked ones are not licensed to work as a taxi. Another option is to take a bus (collectivo) that start from coban and finish at the nearest villages like Tactic, San cristobal and etc.
By walking on the street from the Parque Center to the terminal Market you will feel the Spirit of the Mayan workers from the nearby villages that surround Coban who come to the city in the morning to work and leave afternoon. The people all over, their smile on the morning and Saying hello at afternoon are the view.
the Main Cathedral at the town Center. Semuc Champey about two hours from Coban - There are private tours you can hire to get there that contains also visiting the Caves in lanquin. On 1 Avenida there are several tours guide.
The real magic is all the villages the spread all over. On the the way, all the mountains are covered with beautiful Mayan villages. If you are looking for adventure, just ask some locals from Coban about the villages. In Spanish pueblos like Tactic, Tomtem, Yoho, you will discover a new world.
Every Sunday there is a small crafts market in the center of town. Be sure to offer a lower price or ask what the sellers best price is. Same goes for the market behind the cathedral. Take a tour around and buy some of the local clothing. A Huipil, or women's woven and sometimes embroidered shirt can go for as much as 500 Quetzales / $50 USD or more depending on the quality and detail of the work, so don't be surprised if it seems like a high price for a non-tailored shirt. More simple styles can be found for about 100 Quetzales.
"Al Carbon d'Fiora" serves really good burgers as a local alternative to MacDonalds. It costs about Q25-Q30 for a burger and about Q60 for Churrasco (grilled steak). The food is really good and the place is hygienic although the atmosphere is nothing fancy. Fiora is on Calle Minerva a few blocks inward (toward downtown) from Plaza Magdalena.
A new bar called Antick is located two blocks from the centro parque. The price is cheap and the vibe is very nice, Open all over the week with American and local music like the famous mexican band - Mana.
Near to Antick there is another bar. All over Coban there are something like 5 bars, 2 disco and 1 Stripping club (according to January 2012)
Tourists tend to spend only a night or two in Coban on their way to visit Semuc Champey. However many of the people you will encounter in the hotels will be Guatemalan. There are a number small hotels around the main plaza, most of which are comparable in price. Well established hotels like Casa d'Acuña have built up a great reputation over the years but there are other places to stay which match in quality. Places like Casa-Tenango and Hostel Casa Luna are newer hotels that are becoming popular with guests for their unique styles.
Most buses and microbuses use the northern bus terminal, located about 1.5 km from the city centre, rather than the Monja Blanca station. Travel agencies and Casa d'Acuna will book shuttles.
If you want to go to Semuc Champey, hop on a Microbus for Lanquin (anyone will know where they are, just ask). On arrival you will be hassled by a bunch of dudes trying to sell you tours or get you a ride to your hotel. If you don't have one, these guys would love to sell you one. Know your price before you arrive. Check with your hotel before you arrive to see if they have a free shuttle (most of them do).
Wherever you go, ask the locals how to get there and try it the locals way. It will probably be faster and cheaper than whatever else you had planned.