For me, it's always fun to make Steven laugh and anticipate his retort. We once had each other laughing so hard we soiled ourselves. Not really, but can you imagine? And that's one of our favorite methods to make each other laugh... we go to an extreme and actually use the phrase "can you imagine" or "yeah, like (and then explain the outlandish scenario)."
As for the laughter at my grandfather's prayer, here's the story: Steven, myself, and our father were visiting our grandparents. We had plans for later, (a movie I think), and prior to our departure, we were to have a "quick word of prayer" and my father even indicated (to his father) that we were in a bit of hurry. Well, after ten minutes with no end in sight, I couldn't help but think of how funny it was that even after being told of our haste, my grandfather was covering everything, including salvation for the devil (not really, but can you imagine?). I began to giggle as he took on yet another subject and the more he prayed, the funnier it became to me. Finally, I couldn't hold it in any longer so I went to the restroom and laughed out loud.
When I regained my composure, I returned the prayer vigil, still in full swing, and after a few moments, laughed out loud again with Steven snickering as well. The prayer ended shortly thereafter and my father made us apologize. Later he told us that he almost lost it too. Classic.
I too miss having my brother nearby to create more laughter bonds.