Depends a bit on your fans, for example if they are targeted or not.
Easiest is to set up micro sites selling digital products or similar and then post an update about the cool site you just discovered and place a link to your micro site. The more targeted the friends are, the easier it is. If you have friends with travel related interests you can post travel deals or vouchers from some affiliate network, just think about what could fit best. Don't over spam your friends or they will be gone quickly. Best is to post things they could somehow have a benefit from.