Challenge 1

• http://webcraft-rahim.posterous.com/71381240
• Like the others said, maybe change it to something like "Create a blog and write three sentences about yourself." This will remove some of the mental friction involved with writing a blog post about one's self (which is typically difficult for most people), and will make it easier for people to read and comment other people's blogs. With only three sentences, it leaves the comments open for questions rather than comments, which will create conversations on the person's blogs. ("Wow, you went to New York, I'm going there next week. Where do you recommend I eat?" rather than "Cool story, bro."
• I don't know about the others, but I felt some trepidation with creating a blog. I know companies like Tumblr and Posterous have made it easy, but in my mind I'm still thinking "ugh, this is going to be a pain." It'd be cool if there were one created for me already by P2PU that I could just "claim" and get going on. I know that's basically the same thing as Tumblr, but it seems easier in my mind.

Challenge 2

• http://webcraft-rahim.posterous.com/71383582
• I like this challenge. I think it serves an important purpose.
• I also like the Karate Kid reference, it helps people get into the mindset that this is a small something leading towards a greater whole.

Challenge 3

• I'd ditch the free as in beer or speech part. I think it'll end up confusing more people than it helps.
• Overall, I'm not a fan of this challenge. I think you're better off recommending a text editor for each platform, and listing a few alternatives. For me, I started with any text editor (I think it may have been Notepad), and then when it failed to meet a need, I went looking for another one. It's hard to evaluate a bunch of text editors when you're starting out if you don't know what it is you're looking for.

Challenge 4

• I didn't do this challenge, but like the creativity behind it.
• If I were a student doing the challenges, this is the one I would cheat on by using Google Image search instead of walking around taking photos.

Challenge 5

• I'd ditch the entire domain hacking section. I think it complicates matters more than it needs to.
• This challenge feels really overwhelming and complicated. I think it might be good to break this up into smaller challenges with some extra hand-holding.