I'm becoming peripherally interested in animated GIFs. They seem like the perfect format for adding a little bit of animation to digital comic strips. Animation is nice because it adds two elements that can enhance the humor in the essentially static medium of comics: time and movement. Here are examples of each.
I made this for some birthday folks last month. Wait for it... Bam! Timing!
And here's one I found on the Internets recently that uses motion smartly and to fairly humorous effect.