Have you tried the Random Document web part? You could create a new document type and transform for your quotes.

Hi,

You can store your "quotes" for example in some custom table:

http://devnet.kentico.com/docs/devguide/custom_tables_module_overview.htm

Then you can use "Custom table repeater" web part to display your "quotes". You just need to configure following settings for your "Custom table repeater" web part:

Custom table: Some custom table
ORDER BY expression: NewID()
Select top N documents: 1
Transformation name: some custom table transformation

This web part configured according recommended settings will display one randomly selected item from the custom table at a time.

I hope this will help you.

Best regards,
Miroslav Remias.