Ask HN: Sites with primary colors and white?

I'm designing a little webpage for a Bitcoin tipping project I'm working on, and I really like the simplicity and color scheme of http://square.com/cash

I've seen a few other examples of sites with this theme posted on HN, but I can't remember what they were. If anyone can recall any, I'd really appreciate it, as I'm trying to get some design ideas for my own site.