Check out Missouri Star quilting's youtube channel. A lot of their blocks work up quickly and are really sharp and clever. I've done a few of their demos as my own demos for my small guild.
http://www.youtube.com/user/MissouriQuiltCo
When I do demos at the group I bring my blocks for every stage of the process. squares before cutting, then cut, then sewn - and if there are multiple steps to sewing, I make a block for each step to show it off.. then one that is completed. If it is something that there are multiple ways to assemble the blocks to show off a pattern, I make enough to show off the different patterns. It's a lot of work but it does give me a bunch of blocks to be used for donation quilts down the road.