It is completely coincidence that I started going through the SICP course right before a group has been established on Hacker News. I'm really happy that people are interested in going through the course as a group. It's not really that I am unmotivated to work alone, but being able to talk to people who are around the same chapter and doing the same exercises should prove to be helpful.
 
It is my hope that after this course a similar group will form that wants to go through the MIT Intro to Algorithms course. There have been a couple people on the sicp irc channel that have expressed some interest, so hopefully we can make something of that.
 
What I really like about working in groups is that it also gives things a schedule. As nice as it is to work at your own pace having a schedule that you stick to can be useful as well. I'm ahead of the schedule now, and am going to try to stay ahead. I don't think I've ever been so excited to do homework before. Going through the exercises is pretty fun. I just finished up the Pascal's triangle one which took a bit of thinking. It ended up being really simple, but for some reason I was over thinking it. After some really bad attempts I had to stop myself and just let it sit for a while. I then went back to it today and read the mathematical instructions, and just transfered that over to Scheme. That took about 5 minutes. I guess when you have been working too hard you just need to let a problem sit instead of banging your head against the wall over and over. In this case the problem was really simple and I just was trying to rush through it.
 
Here is the answer that I came up with:
http://github.com/emkay/sicp-exercises/tree/master/chapter1/ex1-12.ss