One who takes a Nazarite vow cannot drink wine (or partake of product that uses grapes). I understand that this is to help the Nazir remain focused on God instead of being overcome by other forces (such as being drunk and doing whatever drunkenness entails, i.e., losing inhibitions, not thinking before acting, etc.).
As a Jew though, can a Nazir drink wine if it is for ritual purposes and not solely personal enjoyment? For example, what comes to mind is wine that is a part of the Passover meal, and also Kiddush.
(Side note: I'm not sure if wine was part of Pesach in the Torah, perhaps it was instituted by Rabbis post-Torah? Perhaps all the incorporations of wine were instituted post-Torah by the Rabbis?)