We confess to having actually purchased the book Learn Tennis in a Weekend. Although rather well designed, the instructional tome was of little help in catalyzing our ascent up our grade school team’s doubles roster. But some things–like Adobe Photoshop–can be learned in a weekend, at least with the right teacher. This weekend in New York City, mediabistro.com is hosting a course that promises to get Mac-based designers proficient in Photoshop in two short days. Instructor Mara Sachs will guide you through everything from color correction and retouching to masking and exporting your work for use in other applications. Similar courses in Illustrator and InDesign are slated for later this spring. So maybe you can learn tennis in a weekend after all–layer tennis, that is.