I'm totally stealing the idea for Minicomics Monday from Johanna--I hope she doesn't mind. In fact, I think it would be great if many comics blogs decided to use Mondays to focus on mini comics!
Armitage Shanks, Arctic Pirate in "Exit Strategy" is a 24 hour comic by Kevin Cannon (part of Big Time Attic and one of the artists on BSC&TL). I normally don't care much for 24-hour comics; sure they're probably an interesting and illuminating exercise for the artist, but as comics they're generally sub-par. But while not up to the polish of his usual work, Cannon still manages to turn in an interesting story (with a plot and everything!) The titular Shanks is hired by a man to track down a pirate who has kidnapped his daughter. Complications ensue. Okay, so it's not a deep plot, but it still makes for a fun read. (read it online here)
Stick Daemonology is by Johane Matte, who brings to this collection of one-page gags the best facility with expressive stick figures I've seen this side of Matt Feazell. The little stick daemons may be the lowest-rung creatures in their hellish void, but that doesn't stop them from joking around and having fun. I chuckled many times reading this, and I suspect you will too.
days, by Karen Knighton, is one of the more original comics I've seen in a while, and is very hard to explain. But I'll try... Throughout this mini are a series of backgrounds, facing each other. in between each background are two translucent pages, each with a character drawn on it, either Yak the Bird or Scissors the Bunny. As you flip the translucent pages, the characters move from one background to the opther, thus reinterpreting the scene. Like I said, hard to describe, but fascinating. If like me you like it when your comics play around with formalism, you stand a good chance of enjoying this.
Mini comics can be notoriously hard to track down. Many artists sell them at conventions, and there are a few comic stores that will carry them. Your best bet is to try ordering them online, either from the artist directly, or from an online shop like Poopsheet.