Having a somewhat freakish passion for fruit salad, I never figured you could improve on the basic concept. But you can: you can make rujak.
Rujak is fruit with a sweet-tangy-spicy sauce and crunchy peanuts. Indonesians especially love rujak with sour fruit like underripe mango; pregnant women are said to crave the sweet-sour combination ... perhaps like pickles-and-ice cream in the US.
Rujak comes in many forms. The Chinese kind one finds in Singapore is called rojak, and has cucumber, bean sprouts and pieces of fried dough in it. In Surabaya they make a famous variant that includes what is usually described as "sliced cow's nose." The recipe below is a simple version that doesn't contain any bovine novelties and shouldn't require too much poking around in specialty food shops - except for the tamarind, which you can generally find in some form at Indian grocery stores.
And here I will say the same old boring thing: you can make this with brown sugar, but it will be tastier if you can get Javanese palm sugar. Adjust the level of sugar and chilis to taste; I haven't tried this recipe but it looks a little sweet.
About 6 cups cubed fruit (mango, Granny Smith apples, pineapple, papaya, firm pear, jicama, grapefruit, cucumber)
3 tablespoons dry roasted peanuts
1 or 2 hot red chilies, sliced and seeded
1/2 cup brown sugar
1 tablespoon tamarind paste, dissolved in 1/2 cup water and strained
Chop the peanuts by hand or in a food processor. Mix with the chilies, brown sugar and tamarind water. Don't over-process; the sauce should be a bit chunky. Combine with fruit. Swoon.