CAMRA Nottingham is holding a beer festival inside the historical grounds of Nottingham Castle, full details on the event can be found online @ http://www.beerfestival.nottinghamcamra.org/
Cost is £10 and for that you will receive entrance into the grounds, a commemorative glass and also 10 mini beer tokens to use at the event . (two mini tokens should buy a third of most beers there). Tickets can be bought in advance but will also be available for purchase on the day.
For those that are interested you will have to make your own way too and from the venue. For your information there is the Red Arrow, Trent Barton Service where the last bus back to Derby is 11.30pm: https://www.trentbarton.co.uk/services/redarrow
Any questions please ask!