we got the perfect pull up bar ($30), and some of that elasticy-stuff and some surgical tubbing (both were cheap). and so that is what we use.
we are looking for some bars outdoors though (we live in an apt, so no yard to build one or we would!). there's a rope climbing thing at the one park that is fun to play around with, but, eh, not the same.
so, we use the low setting for rows and the upper setting for chins. everything else, i tend to use the floor. accursed yoga, makes you use the floor! lol