bandwidth monitoring

Hello, I'll be moving into my college dorm tomorrow and found out that we're limited to 2 gb up/down per day restarting at midnight. If we go over this we get a warning then the banhammer. Any programs to reccomend that will allow me to monitor my daily bandwidth usage(for windows, please)?

my roommate only ever got yelled at when he took up about 18% of the schools bandwidth over a 5 day period.