This was a set that was sold exclusively at Toys 'R Us for an event they had in 2002. It is incredibly rare, but I was able to find it on eBay, so it does show up every now and then. In my case, it was sold with another set. Hopefully you will get lucky when you click on the links below and find it.
The set is of a Quidditch tower and is made from the colors for Ravenclaw (blue and grey) and Hufflepuff (yellow and black). I think the purpose of this was for it to be a companion set to the tower found in Quidditch Practice, but this tower is a bit smaller than the tower found in the other set.
It is one of the few sets that does not include any minifigs, nor are there any creatures. It is just the tower.
Do you live outside the United States?
Although some items on Amazon can be shipped world wide, you will probably have the best luck with eBay and Etsy. Click here to see how to know if an item from those three sites can be shipped outside the U.S.A., as well as how you can buy items found and have them shipped to you even if the store you buy from doesn't ship to your country.(Clicking this will open a new window so you won't lose the page you are currently on.)
This LEGO® set contains small pieces that could be a choke hazard and is not meant for children age three and younger. LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this site.