Before subscribing to a calendar you can preview its events in a big overlayed box that can't be closed unless you have a big monitor (tip: if you can't see the OK button at the bottom of the box, press Enter).
In a surprising move, Google made searching the public calendars the default option, so if you want to restrict your search to the events from your calendars, you have to click on "Search my calendars". The option to search for public events is now available as a barely-visible link in the new gallery. Instead of complicating the interface, Google Calendar should have a single search results page that shows the events from your calendars, then other related events from public calendars.
The fact that Google Calendar complicates itself unnecessarily is obvious if you look at how many options are available to add a new calendar: you can add a public calendar, or the calendar of one of your contacts, you can enter the URL or just upload it. And each option has a different place in the interface.
All in all, searching for public calendars is not too important, so it didn't deserve so much focus (it's like a new search engine that returns web sites, not web pages). The option to search for public events should be available even if you don't use Google Calendar, maybe as a OneBox in Google's main search results.
{ via Google Blogoscoped }