I'm not nostalgic about anything because I never stop doing anything. I still play though Super Mario 64 every now and again, I still watch Pokemon every now again, and I still act like a whiny little brat every now and again.
The days when a certain forum+chat I frequented was really active. It's still alive and enjoyable, but it's not as fun and probably will never be, since replicating the "good ol' days" anywhere is pretty much impossible. Ah well.
I miss my old kindergarten through 8th grade school. I went there for nine years, obviously, and it was a great place. Especially in 8th grade, I had a lot of really fun times at that school, and around it. There were a lot of really nice people there, too, and I especially miss them. I've been in high school for a year now, but once in a while I still miss my old school a little bit.