This is Rambutan (chôm chôm). They're quite sweet, though their seed is a bit woody. The fruit's shell looks kind of funny too. Put three in the photo because two might have a bit of phallic imagery. 

Sapodilla, or xa-pô-chê. The seeds of these are killers. They've got a hook-like thing on them that'll catch in your throat if you swallow them. The fruit has an interesting taste though. Tastes kind of like a malt. If you eat one that's not ripe though, it'll not only taste bad, but it'll dry your mouth out. Figured this out through personal experiences.

This interesting looking fruit is a water apple. Kinda looks like a cross between a bell pepper and an apple. As their name suggests, they have a very high water concentration in them. Can't remember how they taste though.

There are lots of names for this one. Sugar Apple, Sweetsop, and mãng cầu ta in Vietnamese. Interesting fruit, and super, super sweet. Eating too many of these might leave you in a sugar coma. It's skin comes off in pieces, revealing a pasty white flesh chock full of seeds. 

I only know this by the name of Soursop. It's mãng cầu Xiêm in Vietnamese. Like it's name suggests, this one is pretty sour. Like the sweetsop, it's got tonnes of seeds in it. It's quite soft too.