Receiving and Returning Quests
Keep your eyes peeled for monkeys with a yellow exclamation point over their heads. These individuals have available quests to offer.

Monkeys with
grey exclamation points indicate that they will soon have a task for you, but you'll need to do other quests to be ready for their dangerous task.
Use the CTRL key while standing near a quest giver to view the quest details. After a brief conversation, a window appears with the quest name, a brief description, and a list of rewards earned upon completion. Aside from more experience and bananas, quests are an excellent way to earn new and powerful items.
Once you've accepted a quest, the symbol changes to a grey question mark. If you forget what you need to do or require more information about the quest, you can always come back and speak to the quest-giver, or open your map and select the magnifying glass next to the quest for more info.
Once the quest is complete, the icon becomes a yellow question mark indicating you can return to the quest giver and claim your reward.