It is a splendid place. Basically it's a bottle shop and taproom, with a nice comfy lounge where you can enjoy a beer or two inside. Their shop opening times are as follows...
Wednesday: 12:00 - 17:00
Thursday: 12:00 - 21:00
Friday: 12:00 - 21:00
Saturday: 12:00 - 21:00
Sunday: 13:00 - 19:00
The lounge (for drinking inside) doesn't open until 4:00 pm on a Saturday, but it's open from 1:00 pm on a Sunday. We go there on the bus and get there around 3:15 pm.
Next Sunday afternoon they have a band on (probably folk music - they tend to have musicians once a month or so).
They usually have around 10-12 beers or ciders on tap, and they have a few hundred different bottles and cans, including 20 or so German beers, 40 or 50 Belgian beers etc. A lot of local stuff too - Eyam Brewery produce some brilliant beers, and their shelves are always well-stocked.
@sage is from Belper. We met up in Ashbourne the other week at lunchtime, but it was on a Saturday so ended up in the Green Man instead before heading back to Belper (a micropub near the marketplace - can't remember the name).