I'd build a site that has the design of pinterest/instagram or whatever the site is that has the multi-columns of different heights for individual cells.
And the content would simply be from various RSS feeds -- npr, cnn, fox news, times, huff po, etc. Ideally I'd bring it to a level similar to HN, Reddit and Digg with the only difference being the content isn't user generated and you can't "vote" on a story's popularity -- it's timely.
Add the necessary ajax elements so it "stacks" stories on the top of the scaffolds. I should be able to sit on that page and not do a thing and have fresh content load for me.
Then if there's any interest you could easily add more features.
I'd probably write it one day if I weren't so distracted by other things. Shouldn't take much longer than 4 hours to code.