random.org

This site offers true random numbers generated from radio static. This is unlike pseudo-random numbers which are generated by computers and can be predicted. Among various output options, a web interface offers up to 10,000 randomly generated integers which can range from 1 to 1 billion. Users can also download up to 10 megabytes of random bits or even randomly flip a coin (one can even choose the type of coin).

http://Random.org/