Sharing over LAN is indeed the lifeline of many college students, nearly all major technological institues and universities have their own network of over the lan sharing, popularly known as DC or DC++ ease of use and efficiency of this protocol has made it extremely useful in places which have a large number of inter-connected user base.
Windows is already blessed with good DC softwares such as DC++ and Apex DC++ but for Macintosh there still are pretty good option that gets the job done, below is quick reference list of such clients with their pros and cons.
Shakespeer is small and effective DC client for Mac and it does what is says, works fine and has very simple to use interface, add the hub and you are ready to go. Its light and does not clog up the system memory.
But Shakespeer lacks the ability which enables the client to split the downloading files into smaller chunks and and speed up the process, it downloads the entire file at a go.
Elskalt is a cross platform DC client works on multiple operating platforms, it has a interface which closely resembles DC++ and boasts a similar feature set, and has the ability to spilt files and speed up the downloading process. Elskalt outperforms Shakespeer in many areas but has stability issues.