For particular pull requests, I like to have the person responsible go over the PR in an organized fashion, top down where they explain why they solved the problem in this particular way, then go into what they've done and finally a guided tour of the code they've added. This would involve several people on the team and they have the opportunity to ask questions and interact. For how worthwhile that is, I'm surprised it's not brought up as well. I think pair programming and regular PRs are good too but sometimes a presentation style code review is great.
