When it strikes, all I can typically do is wait it out. How hard/often it hits depends on my preventative measures.

Certain topics are more likely to cause writer's block for me. For example, 90% of sci-fi immediately triggers writer's block for me, usually fatal. Fantasy, on the other hand, far less often causes it. Thus, I hate to be a fellow to stick to comfort zones, but on the other hand - I hate to be the fellow that drops off for little good reason.

To keep my interest I typically throw things context relevant into other parts of my (entertainment) life. If I'm doing a mobster roleplay, I watch Empire Boardwalk or something similar. Fantasy roleplay? Chances are I'm not just sucking up fantasy in the roleplay. On the flip side, if I'm doing a roleplay that best fits in the context of game of thrones and I'm watching the Star Wars series from start to end, there tends to be a mental conflict.

I may or may not have a few gigabytes on my USB stick of assorted mood music >.>

While a strong block usually floors me, I do sometimes get through minor ones with changing the goal of what I'm going to post. If I started off with one idea, I might do a plot twist and change it on the spot, rather than force the original idea through a writer's block.