The British Humanist Association have teamed up with Richard Dawkins to push a message on London buses.
It's apparently in response to previous pro-religion bus advertising (see Ariane Sherine's comment article at The Guardian). You can donate to the campaign here. Fund raising has exceeded expectations - perhaps the campaign with run and run (round and round?). As of 28/10/08:
Fundraising target: £5,500.00
Donations so far: £ 110,877.00
Perhaps the message could have been a bit more strident, but I understand from reports on BBC Radio 4 that the wording might be intended to avoid hassle from the Advertising Standards Authority.