The Trip stars Steve Coogan and Rob Brydon as themselves (or exaggerated versions of themselves). The movie consists of them going on a road trip across northern England. While doing this, they stay in quaint bed and breakfasts, visit small towns and take in the nice scenery, eat in many different restaurants, and basically try to one up each other the entire time. Whether they are reciting lines from movies, doing their Michael Caine impressions or singing an Abba song, they are constantly critiquing each other as comics and actors.
Gene Siskel had a great test for the quality of a movie. He would ask if the movie was more entertaining than a documentary of the same actors sitting around having lunch. In this case, that is basically what the movie is and it works.
I don't know their history well, so I did some reading on the web. It turns out this is similar to what they did in their film Tristam Shandy: A Cock and Bull Story. These two have a long history of working together, and much of the movie was improvised. I assume they get along much better together in real life than they do in the movie, but they obviously work well together. Just watching the two of them play off each other is very entertaining.
I enjoyed the movie enough that it makes me want to go check out their previous work together. I am familiar with Steve Coogan, but I had no knowledge of Rob Brydon until this movie. But this is such a genius idea, to take two gifted comedic actors and just stick them in a car together. Imagine if Jack Lemmon and Walter Matheau had done something like this. How cool would that have been?