Couldn't find this posted, so here goes. Feel the power of banning a continent.

Rules For Firewalls

These rules are generated from RIPE LISTS, APNIC LISTS, LACNIC LISTS and ARIN LISTS.
Therefore IP address ranges of these countries [that] are not listed in mentioned LISTS cannot [be] list[ed] [in the rules] below.
As a consequence, note that [. . .] these lists cannot deny all IP-addresses of the above-mentioned countries.
But I think if use this, in almost cases, you can completely deny direct accesses from these countries.

These files are automatically updated around 6 p.m. GMT (7 p.m. CET, 2 a.m. HK/SIN) everyday.
[edited for sense -- Japanese site]

http://www.dayomon.net/fw/