I'm a software engineer at a local university, and I feel I'm able to competently do my job, but recently I've been interested in "filling in" the gaps in my knowledge. I suspect I would have learned some of this in school; for example, I don't have a lot of knowledge of sorting algorithms (something I feel is pretty common in college). So, what knowledge am I likely missing by not going to college that I could study on my own?
Bonus points for listing resources that might put me on the right track!
Some background: I've programmed in PHP, Java, and Ruby (more seriously in Java and Ruby than PHP); I have some experience with C/C++, though my workload doesn't really lend itself to those languages; I work mostly (recently) with the web, using frameworks such as CakePHP and Rails. I'm familiar with SQL (though probably not with some of the theory).
Note: The university I work for has no technical classes, so taking courses on the university's dime is a great idea but not possible for me. :)