Many hotels in Venice will offer you a free trip to Murano. Murano is the island where all the glass makers reside. The glass business was set on Murano hundreds of years ago to assure that all of Venice would not burn down in a glass making accident.
You do not have to feel compelled to buy something at the glass factory just because you accpeted the free transportation there. We went with the intention of buying a special glass souvenir of our trip and the selection of beautiful pieces is amazing. If you do buy, ask for a private boat ride to where ever you are headed next, you will be accomodated.