First of all there's "Experiment 004", a new way to search Steam with a lot more filters. It includes a price slider, options to hide games you own or have wishlisted or that aren't on sale, and more. This new version of search has infinite scrolling as well.
The tweak is an update to the micro trailers of Experiment 001, which create six-second versions of trailers for the time-poor. Now every single game on Steam has one, and they can be browsed by tag here. An entire page of flickering images demanding your attention.
The next Steam Labs experiment will be "Deep Dive", based on the Steam Diving Bell by Lars Doucet, and created in collaboration with him. Diving Bell is a recommender, but unlike the kind that examine your preferences and figure out what to suggest based on that (as the existing Steam Labs Recommender does), this one works by taking a game you suggest to it and then bringing up more things like it. Doucet compares it to a Wikipedia binge, the idea that once you have a topic you're interested in what you want are similar, related topics to explore.
The Deep Dive experiment isn't active yet, but you can mess around with the others over at the Steam Labs page. The updated library will release on September 17 if you've opted into the beta client.