1) Buffy from the present (I think post-Chosen) goes into her body in the past and has to convince Spike to join her group and love her. It is revealed toward the end that Spike had also been sent into his past body and had been there for the entire time she was there, but his past self had the control because he couldn't do anything until Buffy told him she loved him which she did after Graduation I think (maybe it was after Prom). I remember a line like 'It took you two years, Slayer. I've been stuck in that body for two years, and I couldn't say anything about being aware of what was happening because after everything we've been through, you were still too scared to say you love me.' That's not the line exactly but it's the gist of it, and I'm sure there was cursing involved somewhere. I also remember Spike shopping for presents for Buffy and possibly the Scoobies and being really nervous about it.
2) A representative from the PTB or maybe an angel appears at some point, possibly taking over Spike's body for a limited time to explain the knowledge needed to help the Scoobies. He says that Angel is not worthy of being called 'Angel' so he calls him 'Roger' and everyone else starts calling him that too. I believe Xander takes the most joy in calling him 'Roger.' | 
