In addition to oxalis, I will be harvesting and munching on Lamb's quarters and dandelions for the challenge week.
Lamb's Quarters is high in iron, trace minerals, calcium, and potassium, and can be eaten raw or cooked like spinach.
I read that there is an inedible look-a-like to Lamb's Quarters, and you should look for "dusty" looking center leaves to ensure you've got the right plant. All mine are dusty, so I should be good. :o)
Also, dandelions will be on the menu; they are an excellent source of vitamins A, K, and C, calcium, potassium, iron, and manganese, and can be used raw or again, cooked like spinach. In addition, the flowers are edible, and the roots can be roasted and used as a coffee substitute.