All browsers: Want your Google Calendar to look a bit more like a desk calendar — all appointments, no filler? The Mini Google Calendar user script cuts out everything except your data view, relying on keyboard shortcuts for everything else.
Truth be told, most Calendar users probably only use a few functions on Google Calendar's page, like the Quick Add function (hit "q"), the full Create Event link ("c"), and switching between detail views (1-5). Mini Google Calendar looks pretty nice in Safari, especially, given the metal look. For another take on a minimalist Calendar view, try the previously mentioned Helvetical.
Mini Google Calendar is a free download, and should work in Firefox with Greasemonkey, as a Chrome extension, or in other browsers that can apply user scripts.