Semester exams are in progress, and you might be studying, retreating to place of peace and calmness. Noise in general is disturbing and for optimal studying you might even put ear muffles on, to block out disturbing noises.
In a Wired interview with Professor Bart Kosko from the University of Southern California, Kosko explains that noise could actually enhance learning.
To block out disturbances there is always pink noise, which masks out disturbing noises. But beware of lengthy use, as your hearing might get tired and worn by it.

It might be a little late for this semester exam, but it doesn’t hurt trying stu.dicio.us out. At a first glance it may look overwhelming. But it looks like a handy tool to keep track of notes and your class schedules. And best of all online, during classes. Stu.dicio.us integrates Wikipedia and Google to automatically link highlighted words. In addition you can compare notes with other students who attend the same school and classes. (Apparently an account at Facebook gives you even more possibilities.)

The Apple Blog has an entry about another nice note taking application called National Velocity. You might want to take a look at it if your looking at something, that could help your learning experience for next semester.
[...] There is also task list software like this one recently reviewed at 43folders: Task List: Handy student app for tracking assignments. Although this review focuses on helping students, I guess the software can be used to track other assignments as well. It also integrates with iCal, Widgets and Email, but I am not too happy that the only way of online uploading and downloading is currently using .Mac. Task List also lets you add goals and take notes. I previously wrote a suggestion for studying effectively with note taking, also check the link in the comment. 43folders, if you have not heard of 43folders before, it is a good blog about personal productivity. For a forum-like place for resolutions and goals check out: 43things.com. (There are even people wanting to learn Norwegian, yeah!) [...]