I don't like captchas, is there another way to block spam?

A Honeypot is an easy tool to stop spam submittions. To implement this useful technic into your form, you have an example here: 

- Add a text field as first element in your form and give it the name "message_text", then in its advanced settings, turn it off.

- Go to form => advanced tab => more options => submit pieces => begin submit => click "custom" => enter this in the code box:

$this->execPieceByName('ff_InitLib');
if( ff_getSubmit('message_text') != '' )
{
     exit; // well, it should be empty
} 

This should trap most spam bots and you might be able to leave out the captcha.

If there are still some bots making it through, just add some more input fields in the same way and do a check on each as shown above.