Free Flex classes: sample applications:

CodeFlexComboBox (Flex 3 project, zip. ru.codeflex.classes.CodeFlexComboBox.as and ru.codeflex.events.CodeFlexComboBoxEvent.as)
CodeFlexMaskedDateField (Flex 3 project, zip. ru.codeflex.classes.CodeFlexMaskedDateField.as and com.adobe.flex.extras.controls.MaskedTextInput.as)
CodeFlexCenterRotator (as file, zip. ru.codeflex.classes.CodeFlexCenterRotator.as)