The first of those has been a favorite plant of mine since I grew it as a child. Vigna caracalla, or snail vine, is a snail you'll definitely want to have in your garden! The name snail vine comes not from the fact that it's as slow as a snail (actually, just the opposite), but from the one-of-a-kind blossoms that curl and twist like the shell of a snail. It's certainly one of the most unique vines you can grow.
Snail vine can be easily grown from seed and is available from several sources which you can find with a quick Google search. It will grow fairly rapidly to make an 8-10 foot vine (maybe larger in warmer areas) and is perfectly suited to covering a small arbor, trellis or other structure. In warmer zones, it may be perennial (probably borderline in Zone 7b, more reliable Zone 8 and warmer). For those of you in colder areas, I've read that snail vine can be grown in large containers, cut back in the fall and overwintered in a cool, frost-free place to be returned to its outdoor location the following spring where it will resprout, grow and flower the following season. I have not tried this myself (I usually just start from seed each spring), but have talked with several gardeners who overwinter theirs this way with good success.
Flowering typically occurs in late summer and fall and the unique, curled blossoms are more than worth the wait. Full sun to very light shade will give the most flower production. Also, be careful about overfeeding, as you could sacrifice blooms at the expense of foliage.
This is just the tip of the iceberg where unique and unusual plants are concerned, so be sure to stay tuned in the coming weeks and months as I begin posting about many of the wonderful plants I saw on this trip, as well as several other recent plant-related adventures. I know there will be something new you'll want to add to your garden!