Footbag is a growing sport, played mostly in Europe and North America, though there are a rapidly growing number of footbag clubs and players around the world. Frequently referred to as "Hacky Sack" (a product manufactured by Wham-O, Inc.), footbag has existed as a competitive sport in several forms since the 1970's. There are a substantial number of footbag tournaments and festivals each year.
Competitive footbag is governed by the International Footbag Committee (IFC), which publishes the official Rules of Footbag Sports.
A door wall is a sliding-glass door or patio door. The term is yet another example of banal Michigan vernacular, where in the residents latch on to company names, trademark names, marketing terms and product names from local companies. The terms become embedded in the local vocabulary and eventually become accepted as actual valid words and phrases. In this case the term comes from Wallside Windows in Taylor, MI (a large window manufacturer), where 'door wall' is their created word for sliding-glass door.
"Bob! John's gonna bring over them doorwalls from Wallsides on Tuesdee afternoon 'round two-thirty. Get 'er done!"