As a monk, I can make a Flurry of Blows action that lets me make two unarmed strikes with one action. According to the Multiple Attack Penalty section,

The second time you use an attack action during your turn, you take a –5 penalty to your attack roll.

With Flurry, I'm making 2 attacks with 1 action. What is my Multiple Attack Penalty after making a Flurry of Blows?