Another interesting member with edible and curious fruits may be Decaisnea fargesii (blue sausage fruit). It is hardy down to -15 °C and fruit have sweet jelly pulp. It is not well known here as the Akebia is, but looks very interesting....
Yeah, I did my research on that one just last night.
While Useful Tropical Plants quotes two contradictory descriptions of the flavour, one stating that it's insipid, all of the individual taste reviews I found say (after the person gets over the appearance!) that it's pretty good, with a "sweet watermelon" flavour.
Just as a note, it dies back to the ground each year in USDA zone <= 6, but then regrows from its roots.
BTW, if you get out a chance, check out Akebia's nutritional profile (I assume that Decaisnea's is similar). Very healthy, but unusual! For example, the main acid is not citric, malic, succinic, tartaric, oxalic, quinic, etc like in most fruits, but rather lactic! There's a couple other things unusual in its profile, but I can't recall them off the top of my head. It's a bit fattier than most fruits, at 1,5% (although not as much as durian, and certainly nothing like an avocado), and it has an unusually high ash (aka, mineral) content (over 6%). Vitamin C per gram ranges from 1,5x to 14x that of oranges. Apart from all the sugar, it's health food!