Yii Framework - Noob question re widgets, ajax forms, custom listings

Hi all,

I am very new to php frameworks and before taking the plunge to learn it, I hope someone can help with these questions.

How difficult is it create widgets like "most popular articles" with ajax tabs, fade. in/out ajax pop-up sign in box, calendar of events, forums, etc if yii is used as a website cms?

Some very nice sites look like it is powered by drupal kind of cms which I think there are ready made templates for it.

But in yii, do I have to create all the widgets by hand (custom php codes, implement js, css, tediously formating the layouts) or are there ready made extensions, plugins, nice website templates that one can instantly create sites with all the modern looking features?


Some samples that can give you an idea of my questions.
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Stay.com (is the signup popup a plugin? or I have to manually write the jquery/css/html stuff)

www.trendysnack.com (how are all those calendars/sideboxes/listings/shoutout created?)

http://www.footynews.info
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how are the drop down menu created? dynamically by a simple widget based on db or hardcoded in the html?)
The Latest headlines listing - is it a pluging or we have to format it ourselves?
Is the forum a ready made module or the owner actual wrote the codes?

http://www.artfos.com
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multilingual - are the pages stored in db as different language and listed automagically by yii or we still have to write custom codes to retrieve the different language?

I need some pointers here to fully understand how yii can help us.

Thanks alot!!