Some common courtesy for you

In case you didn't know, when going to somebody's house, you always come bearing an offering. This is seen to the host as a token of appreciation. This can be anything as simple as some food or drink. Libations should be brought unopened and unchilled if it is meant to be chilled.

When presenting your host with a bottle of wine or some libations, it can be assumed that it is a gift for consuming later. If the host decides to open it now, then it can be drank, but never assume that he/she wants to. Bringing food, beer, or other consumables usually indicates that everyone will partake in the night of the invitation. Flowers are also a great offering especially for an older couple. Chocolates and confections are great for grandparents. I like bringing my grandparents something homemade such as cookies or some soup.