The most basic of garb items. If you don't have anything else, you can get away with a t-tunic for some time, or if you're lazy and like comfy clothes to run around and get messy in - all the time.
This is basically just a large, long t-shirt or dress with either long or short sleeves.
Both males and females wanting to recreate the look of early period dress use the T-tunic, however depending on what time or place you wish to research, they can become rather complex. Often, to make the outfit look prettier, trim can be sewn on as edging, either commercially purchased or made by tablet weaving.
A T-tunic looks quite nice when combined with a tabard, although can be worn as is. The tunic is the world's easiest piece of SCA clothing to make.
How do you make a T-tunic?
Some links with pictures and intructions to help make several different styles of tunic.