William Wilberforce would prepare conversational “launchers” to “move the conversation to more ‘relevant’ matters”:

One final aspect of his Wilberforce’s life and spirituality was that of the importance he attached to sharing his evangelical faith, something he would do primarily through his ‘Friends Papers’ – his use of ‘Launchers.’ Wilberforce could easily spend an hour preparing these ‘launchers’, openers that he could use to move the conversation to more ‘relevant’ matters in his mind. We learn that among Wilberforce’s manuscripts was discovered one such ‘Friends’ document that he had marked ‘to be looked at each Sunday.’ On the sheets he had listed thirty of his friends, and written aside each of the names he had attached thoughts of how he could personally help each of them toward Christ.

Interestingly though, it appears to have been common knowledge amongst many of his friends and acquaintances, that this indeed was Wilberforce’s plan, but so attractive as a potential guest was he viewed by them, that no one thought anything of it. Indeed so much so, that one contemporary recorded that, ‘when the little man came in late to a dinner party, bristling, maybe, with “launchers”, every face lighted up with pleasure at his entry.’

Source: William Wilberforce: His Unpublished Spiritual Journals (Biography)