Recently, a user has been posting links in several places to an anonymous .RAR file. This is just a reminder, but you should never download suspicious files from anyone. If you see someone posting unsolicited links, your best bet is to contact an admin. Or, if you get a link posted on your message wall, remove it and also alert an admin. It's better to be safe than sorry about things like this. Only download files from trusted sources, and even then, be cautious of links you recieve that seem unusual or "out of character" for the person sending them.
For anyone looking to send files, it's recommended to be as up-front about things as possible. Talk to as many people, especially admins, as you can. Make sure that they know what's up, and what is in the file you want to distribute. You may have a great idea for a creepypasta that can only be achieved by distributing files in secret, but if the administrative staff don't know what's going on, your account could be suspended due to suspicious activity. The degree of mystery you can get from playing off your story as real isn't worth losing your account indefinitely. These days, unfortunately, our sense of caution has to outweigh our sense of curiosity, at least for the most part.
Lastly, here are a couple sites that do free virus scans on files. You still should be wary of running .EXE files you find, as they may be unrecognized forms of malware, but these will help find common traps.