So i came across this and decided to drop it here. I'm mostly on Facebook looking at funny memes and most likely follow any page that makes me laugh.
Depending on what your page is about you can post funny related memes every now and then, people see it, they like it and are most likely to share it. That way they are not just sharing a funny meme, the are giving your page or group more exposure and increased chance people are going to follow your page.
You can make a meme of your own by cutting down a funny YouTube video into a meme/gif or using any other already made related meme you find.
A second way is by following groups with high number of people, when you make a post you can share your posts with these groups. If you have a site, you can place links to your site. This way you increase organic traffic to your site.