Random Hall is the smallest dorm at MIT, named after the (fictional) J Arthur Random. Officially it is building NW61, since it is west of Mass Ave and north of the railroad. The address is 282 and 290 Mass Ave. Is it typically considered one of the east campus dorms, along with East Campus, Senior House, and sometimes Bexley.
More information is available at http://web.mit.edu/random-hall/www/ .