If you want to travel in the Netherlands, using public transportation (trains, trams, busses) you might want to buy an OV chipcard which is valid in public transport in the entire country. You can buy it at the airport and all major train stations, or online.
In Utrecht you can buy an OV chipcard at Central Station, and at the following shops: Primera, AKO, Readshop, Bruna and supermarkets.
The retail price for the card is 7,50 euro and you can load your OV chipcard with credit at a reloading device, which can be found at railway stations and affiliated resellers. The card is valid for four years, so you can also use it during future visits to the Netherlands. You can still travel without an OV chipcard and buy train tickets at the station and bus tickets in the bus, but then the total travel costs during the workshop might be higher. Find more information on the OV chipcard website