A tart is a popular food at SCA feasts. Tarts are easy to eat because you often don't need a plate or bowl to eat them off. They're simply a pastry base (often shortcrust pastry) with a filling in the middle. There is a widespread misconception that the difference between a pie and a tart is that a tart does not have a pastry lid and tends to be small. In fact, there is no simple rule by which the two may be distinguished from each other, except that if the traditional name of a recipe calls it a "tart" or a "pie", then that is what it is.
You can fill tarts (and pies!) with whatever you feel like, and they're very easy to make. They can be sweet or savoury, and despite what many people in the SCA believe, you can make a savory tart without using either cloves or sultanas. You can make small tarts - known as tartlettes - or big tarts. A popular Canadian tart is the butter-pecan tart, which is apparently unheard-of in the United States (Canadian Butter-tart afficionadoes going to Pennsic are therefore advised to bring their own supply).
Note: From an English perspective, tart has a secondary meaning, related to the lower end of the wenching sorority, and ladies of negotiable affection. You can eat this sort of tart, but . . . the difference between a wench and a tart is basically that a tart doesn't require persuading, just gold.