Hans has got our Inline expandable post summaries (a.k.a Peekaboo posts) hack working with old Blogger template also! So, those of you who are waiting for the golden invitation for switching to Beta, can have the hack up and running in your blog now. And be rest assured that the hack is also available after switching to Beta. Here's Hans's post on this topic.
Hoctro has a few nice hacks too in his place in Blogosphere - one for displaying vertical tabs with labels and another to create 3 columns (even 4 or 5) with Yahoo! CSS Grid system. Why live the simple life with 2 columns, I say ;)