Where do I find contests?

On the home page, right on top there is a header which changes every minute or so. On that, you can find the ongoing contests

You can also find them here 

Right now, there are 2 open contests :

http://www.indiblogger.in/indistuff/8/

http://www.indiblogger.in/indistuff/7/

One can't apply for samples in the above two Indistuffs but can submit there entries 

Yes! But you can submit an entry and win prizes without applying for the sample. 

Indistuff 7, Indistuff 8 and Indistuff 9, Kiddo.

Dove, Tresseme and Sunsilk.

7 is not a valid contest - as there are no prizes 

Yes, it should have been 8 and 9 instead of 7 and 8

http://www.indiblogger.in/indistuff/8/

http://www.indiblogger.in/indistuff/9/

I can tell how good is your product without even using it  It's a winner 

All the contests can be found in the Slider under the header in the home page. If you want to see all the current and previous contests then you should follow the way Ranjith has mentioned.