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/