Today was the only pre-booked tour on my schedule. Some friends were going on a bus toor to Tara and Newgrange and I took the opportunity to tag along. Tara is the sort of site where you need some deep background to understand what you're seeing. The tour guide did a great job of sketching in the background in the available time, but I suspect for many of the tour members it was simply a big hill with a bunch of bumps on it. The tour was enjoyable, but there was a certain sense of being processed through a tourism machine.