1. Hot Vit Lon (young fertilized duck egg)
This is also referred to as Balut in some countries. It's basically a fertilized duck egg which you crack open and eat ofter you cook it for a while. I remember seeing trays stacked full of these eggs the last time I went to a major Asian supermarket. Do these taste good? Well, if you can get past what is basically a fully formed baby duck (minus feathers) staring up at you then it tastes surprisingly decent. The egg contains alot of water which many people sip because it's supposed to be highly flavored. Just remember to throw away the waxy white eraser like lump you find at the bottom since it's pretty inedible.
2. sầu riêng (Durian)
Durian is a polarizing fruit; some people love it and can't get enough of it and some people can't stomach the stuff. Durian are notoriously difficult to grow and take alot of time to mature which contributes to the hefty price of the fruit. Another aspect that contributes to people's wariness of durian is the difficulty in opening it. Durian are covered with tough prickly spines which protect soft pale yellowish fruit. The fruit is extremely pungent and some have compared its smell to farts. For this reason, many Asian hotels ban durian on their premises. If you would like to try durian but do not want to deal with the complicated task of opening it, then you can probably find tubes of frozen durian at an Asian supermarket. The taste doesn't quite compare to fresh durian but it's an easier and less messy alternative.
3.Kho Qua (Bitter melo)
Meat stuffed bitter melon is a comfort food for many Vietnamese people but it's definitely an acquired taste. Even young Vietnamese people have trouble eating this dish but alot of elderly Vietnamese people enjoy this dish immensely. Bitter melon is as its name suggest incredibly bitter. It's bitterness is so overpowering that it manages to surround your whole mouth. Reportedly, bitter melon has cooling properties which makes it very healthy for you.
*I have eaten everything on this list numerous times except number 3.** All pictures are from Wikipedia except the bitter melon picture.