Seriously, what kind of flyer blog would this be if I didn't cite the classics? Stefan Sagmeister (a very articulate designer, author, and lecturer) puts out some abstract ideas behind his work. His pieces bear his signature handmade arts+crafts style, which uses simple elements and combines them into an eye-catching concept. For example, the Adobe Awards poster employed the use of 2500 coffee cups to make the image.
For those of you not familiar with ISO50/Tycho/Scott Hansen, he's well known for designing beautiful cd covers, concert posters, and a few flyers. Most of his work is done as a poster (as is the last image in the post), but his flyers evoke the same natural/vivid color schemes with a contrast of an organic feel with geometric shapes that just reach out to your eye. This is just a concise sampling of his work, I really recommend his blog to check out his extensive portfolio of posters.
Consistent eye-catching colors that are clean and not forced, and the thing just looks textured. After much investigating, can't figure who's responsible for this piece. Done for a launch party at Love. via Showtrotta.